In , on 12/13/03
at 05:34 AM, "Mark D. Zacharias" said:

Just don't be too surprised if the amp blows up.
The technique may indeed work - but consider the common light bulb. At
power-on or power-off is the most common time for it to fail. Sudden
application or removal of voltage causes current surges, and output
transistors change their physical characteristics a bit from thermal
expansion/contracting as the piece warms up and cools down. This is
normal wear and tear to be sure, but be aware you may be accelerating
the process significantly.

Mark Z.

Repeat 30 times. At this
point, I'll bet your problem is gone.

If the amplifier is otherwise healthy, it's no worse than a sudden bass
note. You only need to play the amp at these volume levels for a
fraction of a second. If you start cold, even after the 30 repetitions,
the amp only warms up to a regular working temperature.

If you are worried about the temperature rise, wait 30 seconds between
repetitions.

I've been using this trick for decades and haven't lost any units. (I
have a fully equipped test bench and check the amplifiers afterward --
there's never been a problem.)

Initially, everyone blinks and squints a bit when I describe this
technique. Most, particularly engineers, like the idea and add it to
their bag of tricks.

If you are really bothered about the turn-on surge, unsolder one leg of
the protection relay coil and flash the contacts by pulsing the relay.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/13/03
at 05:34 AM, "Mark D. Zacharias" said:

Just don't be too surprised if the amp blows up.
The technique may indeed work - but consider the common light bulb. At
power-on or power-off is the most common time for it to fail. Sudden
application or removal of voltage causes current surges, and output
transistors change their physical characteristics a bit from thermal
expansion/contracting as the piece warms up and cools down. This is
normal wear and tear to be sure, but be aware you may be accelerating
the process significantly.

Mark Z.

Repeat 30 times. At this
point, I'll bet your problem is gone.

If the amplifier is otherwise healthy, it's no worse than a sudden bass
note. You only need to play the amp at these volume levels for a
fraction of a second. If you start cold, even after the 30 repetitions,
the amp only warms up to a regular working temperature.

If you are worried about the temperature rise, wait 30 seconds between
repetitions.

I've been using this trick for decades and haven't lost any units. (I
have a fully equipped test bench and check the amplifiers afterward --
there's never been a problem.)

Initially, everyone blinks and squints a bit when I describe this
technique. Most, particularly engineers, like the idea and add it to
their bag of tricks.

If you are really bothered about the turn-on surge, unsolder one leg of
the protection relay coil and flash the contacts by pulsing the relay.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/13/03
at 05:34 AM, "Mark D. Zacharias" said:

Just don't be too surprised if the amp blows up.
The technique may indeed work - but consider the common light bulb. At
power-on or power-off is the most common time for it to fail. Sudden
application or removal of voltage causes current surges, and output
transistors change their physical characteristics a bit from thermal
expansion/contracting as the piece warms up and cools down. This is
normal wear and tear to be sure, but be aware you may be accelerating
the process significantly.

Mark Z.

Repeat 30 times. At this
point, I'll bet your problem is gone.

If the amplifier is otherwise healthy, it's no worse than a sudden bass
note. You only need to play the amp at these volume levels for a
fraction of a second. If you start cold, even after the 30 repetitions,
the amp only warms up to a regular working temperature.

If you are worried about the temperature rise, wait 30 seconds between
repetitions.

I've been using this trick for decades and haven't lost any units. (I
have a fully equipped test bench and check the amplifiers afterward --
there's never been a problem.)

Initially, everyone blinks and squints a bit when I describe this
technique. Most, particularly engineers, like the idea and add it to
their bag of tricks.

If you are really bothered about the turn-on surge, unsolder one leg of
the protection relay coil and flash the contacts by pulsing the relay.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

There's been a couple threads lately involving units damged by repeated
power on-off cycling, usually by children.

Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/13/03
at 05:34 AM, "Mark D. Zacharias" said:

Just don't be too surprised if the amp blows up.
The technique may indeed work - but consider the common light bulb. At
power-on or power-off is the most common time for it to fail. Sudden
application or removal of voltage causes current surges, and output
transistors change their physical characteristics a bit from thermal
expansion/contracting as the piece warms up and cools down. This is
normal wear and tear to be sure, but be aware you may be accelerating
the process significantly.

Mark Z.

Repeat 30 times. At this
point, I'll bet your problem is gone.

If the amplifier is otherwise healthy, it's no worse than a sudden bass
note. You only need to play the amp at these volume levels for a
fraction of a second. If you start cold, even after the 30 repetitions,
the amp only warms up to a regular working temperature.

If you are worried about the temperature rise, wait 30 seconds between
repetitions.

I've been using this trick for decades and haven't lost any units. (I
have a fully equipped test bench and check the amplifiers afterward --
there's never been a problem.)

Initially, everyone blinks and squints a bit when I describe this
technique. Most, particularly engineers, like the idea and add it to
their bag of tricks.

If you are really bothered about the turn-on surge, unsolder one leg of
the protection relay coil and flash the contacts by pulsing the relay.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

There's been a couple threads lately involving units damged by repeated
power on-off cycling, usually by children.

Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/13/03
at 05:34 AM, "Mark D. Zacharias" said:

Just don't be too surprised if the amp blows up.
The technique may indeed work - but consider the common light bulb. At
power-on or power-off is the most common time for it to fail. Sudden
application or removal of voltage causes current surges, and output
transistors change their physical characteristics a bit from thermal
expansion/contracting as the piece warms up and cools down. This is
normal wear and tear to be sure, but be aware you may be accelerating
the process significantly.

Mark Z.

Repeat 30 times. At this
point, I'll bet your problem is gone.

If the amplifier is otherwise healthy, it's no worse than a sudden bass
note. You only need to play the amp at these volume levels for a
fraction of a second. If you start cold, even after the 30 repetitions,
the amp only warms up to a regular working temperature.

If you are worried about the temperature rise, wait 30 seconds between
repetitions.

I've been using this trick for decades and haven't lost any units. (I
have a fully equipped test bench and check the amplifiers afterward --
there's never been a problem.)

Initially, everyone blinks and squints a bit when I describe this
technique. Most, particularly engineers, like the idea and add it to
their bag of tricks.

If you are really bothered about the turn-on surge, unsolder one leg of
the protection relay coil and flash the contacts by pulsing the relay.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

There's been a couple threads lately involving units damged by repeated
power on-off cycling, usually by children.

Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/13/03
at 05:34 AM, "Mark D. Zacharias" said:

Just don't be too surprised if the amp blows up.
The technique may indeed work - but consider the common light bulb. At
power-on or power-off is the most common time for it to fail. Sudden
application or removal of voltage causes current surges, and output
transistors change their physical characteristics a bit from thermal
expansion/contracting as the piece warms up and cools down. This is
normal wear and tear to be sure, but be aware you may be accelerating
the process significantly.

Mark Z.

Repeat 30 times. At this
point, I'll bet your problem is gone.

If the amplifier is otherwise healthy, it's no worse than a sudden bass
note. You only need to play the amp at these volume levels for a
fraction of a second. If you start cold, even after the 30 repetitions,
the amp only warms up to a regular working temperature.

If you are worried about the temperature rise, wait 30 seconds between
repetitions.

I've been using this trick for decades and haven't lost any units. (I
have a fully equipped test bench and check the amplifiers afterward --
there's never been a problem.)

Initially, everyone blinks and squints a bit when I describe this
technique. Most, particularly engineers, like the idea and add it to
their bag of tricks.

If you are really bothered about the turn-on surge, unsolder one leg of
the protection relay coil and flash the contacts by pulsing the relay.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/13/03
at 11:01 PM, "Mark D. Zacharias" said:


There's been a couple threads lately involving units damged by
repeated power on-off cycling, usually by children.

It's not an issue.

If you cycle fast enough, the filter capacitors will not discharge
completely and the turn-on transient will be smaller than for a normal
turn-on. The major "risk" is for the power switch, which will be
carrying more current at the instant of turn off than if the unit had
been idling at the time of shutdown. (unfortunately, it was years of
soft shutdowns that caused the protection relay to get into trouble in
the first place.)

If 30 extra power switch cycles are offensive, then apply my treatment
once a day for thirty days being careful to perform the procedure only
once at the end of the listening day. That way there are no extra power
cycles over the life of the unit and the unit will have plenty of time
to cool off.

Even though the situation may improve after the first day, I recommend
continuing for the full 30 days.

---

Anyone who feels uncomfortable with the procedure should not attempt
it. For everyone else, you'll find it works like a charm. The down side
is that, if you have misdiagnosed the fundamental problem or the relay
is seriously burned, the technique won't accomplish anything and you'll
squander about four minutes of your life.

This is not a procedure I apply to every unit that crosses my bench.
The problem described at the beginning of this thread is a classic
protection relay issue that is usually resolved after using my
technique.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/13/03
at 11:01 PM, "Mark D. Zacharias" said:


There's been a couple threads lately involving units damged by
repeated power on-off cycling, usually by children.

It's not an issue.

If you cycle fast enough, the filter capacitors will not discharge
completely and the turn-on transient will be smaller than for a normal
turn-on. The major "risk" is for the power switch, which will be
carrying more current at the instant of turn off than if the unit had
been idling at the time of shutdown. (unfortunately, it was years of
soft shutdowns that caused the protection relay to get into trouble in
the first place.)

If 30 extra power switch cycles are offensive, then apply my treatment
once a day for thirty days being careful to perform the procedure only
once at the end of the listening day. That way there are no extra power
cycles over the life of the unit and the unit will have plenty of time
to cool off.

Even though the situation may improve after the first day, I recommend
continuing for the full 30 days.

---

Anyone who feels uncomfortable with the procedure should not attempt
it. For everyone else, you'll find it works like a charm. The down side
is that, if you have misdiagnosed the fundamental problem or the relay
is seriously burned, the technique won't accomplish anything and you'll
squander about four minutes of your life.

This is not a procedure I apply to every unit that crosses my bench.
The problem described at the beginning of this thread is a classic
protection relay issue that is usually resolved after using my
technique.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/13/03
at 11:01 PM, "Mark D. Zacharias" said:


There's been a couple threads lately involving units damged by
repeated power on-off cycling, usually by children.

It's not an issue.

If you cycle fast enough, the filter capacitors will not discharge
completely and the turn-on transient will be smaller than for a normal
turn-on. The major "risk" is for the power switch, which will be
carrying more current at the instant of turn off than if the unit had
been idling at the time of shutdown. (unfortunately, it was years of
soft shutdowns that caused the protection relay to get into trouble in
the first place.)

If 30 extra power switch cycles are offensive, then apply my treatment
once a day for thirty days being careful to perform the procedure only
once at the end of the listening day. That way there are no extra power
cycles over the life of the unit and the unit will have plenty of time
to cool off.

Even though the situation may improve after the first day, I recommend
continuing for the full 30 days.

---

Anyone who feels uncomfortable with the procedure should not attempt
it. For everyone else, you'll find it works like a charm. The down side
is that, if you have misdiagnosed the fundamental problem or the relay
is seriously burned, the technique won't accomplish anything and you'll
squander about four minutes of your life.

This is not a procedure I apply to every unit that crosses my bench.
The problem described at the beginning of this thread is a classic
protection relay issue that is usually resolved after using my
technique.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In many cases it is a residual small dc offset, and/or high-volume music
present when the relay "hits" or when it's disengaged, which caused the
relay problem in the first place.

I assumed this fix was for situations where it was impractical to remove and
service the relay.

If it's on the bench anyway, I would simply remove it and service it
properly, assuming that was possible.

Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/13/03
at 11:01 PM, "Mark D. Zacharias" said:


There's been a couple threads lately involving units damged by
repeated power on-off cycling, usually by children.

It's not an issue.

If you cycle fast enough, the filter capacitors will not discharge
completely and the turn-on transient will be smaller than for a normal
turn-on. The major "risk" is for the power switch, which will be
carrying more current at the instant of turn off than if the unit had
been idling at the time of shutdown. (unfortunately, it was years of
soft shutdowns that caused the protection relay to get into trouble in
the first place.)

If 30 extra power switch cycles are offensive, then apply my treatment
once a day for thirty days being careful to perform the procedure only
once at the end of the listening day. That way there are no extra power
cycles over the life of the unit and the unit will have plenty of time
to cool off.

Even though the situation may improve after the first day, I recommend
continuing for the full 30 days.

---

Anyone who feels uncomfortable with the procedure should not attempt
it. For everyone else, you'll find it works like a charm. The down side
is that, if you have misdiagnosed the fundamental problem or the relay
is seriously burned, the technique won't accomplish anything and you'll
squander about four minutes of your life.

This is not a procedure I apply to every unit that crosses my bench.
The problem described at the beginning of this thread is a classic
protection relay issue that is usually resolved after using my
technique.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In many cases it is a residual small dc offset, and/or high-volume music
present when the relay "hits" or when it's disengaged, which caused the
relay problem in the first place.

I assumed this fix was for situations where it was impractical to remove and
service the relay.

If it's on the bench anyway, I would simply remove it and service it
properly, assuming that was possible.

Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/13/03
at 11:01 PM, "Mark D. Zacharias" said:


There's been a couple threads lately involving units damged by
repeated power on-off cycling, usually by children.

It's not an issue.

If you cycle fast enough, the filter capacitors will not discharge
completely and the turn-on transient will be smaller than for a normal
turn-on. The major "risk" is for the power switch, which will be
carrying more current at the instant of turn off than if the unit had
been idling at the time of shutdown. (unfortunately, it was years of
soft shutdowns that caused the protection relay to get into trouble in
the first place.)

If 30 extra power switch cycles are offensive, then apply my treatment
once a day for thirty days being careful to perform the procedure only
once at the end of the listening day. That way there are no extra power
cycles over the life of the unit and the unit will have plenty of time
to cool off.

Even though the situation may improve after the first day, I recommend
continuing for the full 30 days.

---

Anyone who feels uncomfortable with the procedure should not attempt
it. For everyone else, you'll find it works like a charm. The down side
is that, if you have misdiagnosed the fundamental problem or the relay
is seriously burned, the technique won't accomplish anything and you'll
squander about four minutes of your life.

This is not a procedure I apply to every unit that crosses my bench.
The problem described at the beginning of this thread is a classic
protection relay issue that is usually resolved after using my
technique.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In many cases it is a residual small dc offset, and/or high-volume music
present when the relay "hits" or when it's disengaged, which caused the
relay problem in the first place.

I assumed this fix was for situations where it was impractical to remove and
service the relay.

If it's on the bench anyway, I would simply remove it and service it
properly, assuming that was possible.

Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/13/03
at 11:01 PM, "Mark D. Zacharias" said:


There's been a couple threads lately involving units damged by
repeated power on-off cycling, usually by children.

It's not an issue.

If you cycle fast enough, the filter capacitors will not discharge
completely and the turn-on transient will be smaller than for a normal
turn-on. The major "risk" is for the power switch, which will be
carrying more current at the instant of turn off than if the unit had
been idling at the time of shutdown. (unfortunately, it was years of
soft shutdowns that caused the protection relay to get into trouble in
the first place.)

If 30 extra power switch cycles are offensive, then apply my treatment
once a day for thirty days being careful to perform the procedure only
once at the end of the listening day. That way there are no extra power
cycles over the life of the unit and the unit will have plenty of time
to cool off.

Even though the situation may improve after the first day, I recommend
continuing for the full 30 days.

---

Anyone who feels uncomfortable with the procedure should not attempt
it. For everyone else, you'll find it works like a charm. The down side
is that, if you have misdiagnosed the fundamental problem or the relay
is seriously burned, the technique won't accomplish anything and you'll
squander about four minutes of your life.

This is not a procedure I apply to every unit that crosses my bench.
The problem described at the beginning of this thread is a classic
protection relay issue that is usually resolved after using my
technique.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/14/03
at 06:39 AM, "Mark D. Zacharias" said:

In many cases it is a residual small dc offset, and/or high-volume
music present when the relay "hits" or when it's disengaged, which
caused the relay problem in the first place.

Unless the offset is high enough to cause some contact heating, I claim
that the offset will tend to prevent or minimize the problem.

Most people turn down the volume before turning off the unit.
Essentially, this is operating the relay in the "dry" region, but it
was never designed to operate there. Speaker relays should be operated
such that there is enough current flowing at break time to burn off the
contact surface contamination. If the relay continually opens without
any significant current to break, it's only a matter of time till the
contact becomes intermittent.

Yes, I can imagine seriously burned contacts becoming a problem, but
I've never observed it. The problem relays I encounter have been
chronically starved for current at break time.

I assumed this fix was for situations where it was impractical to
remove and service the relay.

If it's on the bench anyway, I would simply remove it and service it
properly, assuming that was possible.

Yes, if the customer will pay for it.

Many times they'll call, barely able to communicate this (to them)
bizarre behavior, and I'll have the customer do my procedure at home.
You can argue that I will lose some immediate income, but they will
remember that I treated them well, saved them the bother of a nuisance
service call, and they'll be back later and/or recommend me to their
friends.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/14/03
at 06:39 AM, "Mark D. Zacharias" said:

In many cases it is a residual small dc offset, and/or high-volume
music present when the relay "hits" or when it's disengaged, which
caused the relay problem in the first place.

Unless the offset is high enough to cause some contact heating, I claim
that the offset will tend to prevent or minimize the problem.

Most people turn down the volume before turning off the unit.
Essentially, this is operating the relay in the "dry" region, but it
was never designed to operate there. Speaker relays should be operated
such that there is enough current flowing at break time to burn off the
contact surface contamination. If the relay continually opens without
any significant current to break, it's only a matter of time till the
contact becomes intermittent.

Yes, I can imagine seriously burned contacts becoming a problem, but
I've never observed it. The problem relays I encounter have been
chronically starved for current at break time.

I assumed this fix was for situations where it was impractical to
remove and service the relay.

If it's on the bench anyway, I would simply remove it and service it
properly, assuming that was possible.

Yes, if the customer will pay for it.

Many times they'll call, barely able to communicate this (to them)
bizarre behavior, and I'll have the customer do my procedure at home.
You can argue that I will lose some immediate income, but they will
remember that I treated them well, saved them the bother of a nuisance
service call, and they'll be back later and/or recommend me to their
friends.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/14/03
at 06:39 AM, "Mark D. Zacharias" said:

In many cases it is a residual small dc offset, and/or high-volume
music present when the relay "hits" or when it's disengaged, which
caused the relay problem in the first place.

Unless the offset is high enough to cause some contact heating, I claim
that the offset will tend to prevent or minimize the problem.

Most people turn down the volume before turning off the unit.
Essentially, this is operating the relay in the "dry" region, but it
was never designed to operate there. Speaker relays should be operated
such that there is enough current flowing at break time to burn off the
contact surface contamination. If the relay continually opens without
any significant current to break, it's only a matter of time till the
contact becomes intermittent.

Yes, I can imagine seriously burned contacts becoming a problem, but
I've never observed it. The problem relays I encounter have been
chronically starved for current at break time.

I assumed this fix was for situations where it was impractical to
remove and service the relay.

If it's on the bench anyway, I would simply remove it and service it
properly, assuming that was possible.

Yes, if the customer will pay for it.

Many times they'll call, barely able to communicate this (to them)
bizarre behavior, and I'll have the customer do my procedure at home.
You can argue that I will lose some immediate income, but they will
remember that I treated them well, saved them the bother of a nuisance
service call, and they'll be back later and/or recommend me to their
friends.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

Barry could this be done with just using an old pair of headphones {not on
the head of course }? Is the speaker relay in the cct when headphones are
plugged in ?

Barry could this be done with just using an old pair of headphones {not on
the head of course }? Is the speaker relay in the cct when headphones are
plugged in ?

Barry could this be done with just using an old pair of headphones {not on
the head of course }? Is the speaker relay in the cct when headphones are
plugged in ?

In , on 12/15/03
at 11:34 AM, "dickydoo" said:

Barry could this be done with just using an old pair of headphones
{not on the head of course }? Is the speaker relay in the cct when
headphones are plugged in ?

It won't be effective.

The relay contacts must be carrying significant current at the instant
they open. The technique will usually work if you connect the amplifier
to a high powered eight or four Ohm resistor, but it will work better
when connected to speakers. Headphones draw very little current.

Usually, but not always, the headphone jack is connected at the same
point (after the relay) as the speakers.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/15/03
at 11:34 AM, "dickydoo" said:

Barry could this be done with just using an old pair of headphones
{not on the head of course }? Is the speaker relay in the cct when
headphones are plugged in ?

It won't be effective.

The relay contacts must be carrying significant current at the instant
they open. The technique will usually work if you connect the amplifier
to a high powered eight or four Ohm resistor, but it will work better
when connected to speakers. Headphones draw very little current.

Usually, but not always, the headphone jack is connected at the same
point (after the relay) as the speakers.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/15/03
at 11:34 AM, "dickydoo" said:

Barry could this be done with just using an old pair of headphones
{not on the head of course }? Is the speaker relay in the cct when
headphones are plugged in ?

It won't be effective.

The relay contacts must be carrying significant current at the instant
they open. The technique will usually work if you connect the amplifier
to a high powered eight or four Ohm resistor, but it will work better
when connected to speakers. Headphones draw very little current.

Usually, but not always, the headphone jack is connected at the same
point (after the relay) as the speakers.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

Okay, thanks.

Okay, thanks.

Okay, thanks.

I think you've got it backwards here. High current when the circuit is
broken causes inevitable sparking, thus pitting and carbonization. Sometimes
the contacts actually weld together under extreme conditions. Age and
oxidation cause the bad connections you speak of, not lack of current flow
when the relay closes or opens.

Besides, the technique you describe must take some time to accomplish -
removing the relay for proper service probably wouldn't take any longer.

Mark Z.


Speaker relays should be operated
such that there is enough current flowing at break time to burn off the
contact surface contamination.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/14/03
at 06:39 AM, "Mark D. Zacharias" said:

In many cases it is a residual small dc offset, and/or high-volume
music present when the relay "hits" or when it's disengaged, which
caused the relay problem in the first place.

Unless the offset is high enough to cause some contact heating, I claim
that the offset will tend to prevent or minimize the problem.

Most people turn down the volume before turning off the unit.
Essentially, this is operating the relay in the "dry" region, but it
was never designed to operate there. Speaker relays should be operated
such that there is enough current flowing at break time to burn off the
contact surface contamination. If the relay continually opens without
any significant current to break, it's only a matter of time till the
contact becomes intermittent.

Yes, I can imagine seriously burned contacts becoming a problem, but
I've never observed it. The problem relays I encounter have been
chronically starved for current at break time.

I assumed this fix was for situations where it was impractical to
remove and service the relay.

If it's on the bench anyway, I would simply remove it and service it
properly, assuming that was possible.

Yes, if the customer will pay for it.

Many times they'll call, barely able to communicate this (to them)
bizarre behavior, and I'll have the customer do my procedure at home.
You can argue that I will lose some immediate income, but they will
remember that I treated them well, saved them the bother of a nuisance
service call, and they'll be back later and/or recommend me to their
friends.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

I think you've got it backwards here. High current when the circuit is
broken causes inevitable sparking, thus pitting and carbonization. Sometimes
the contacts actually weld together under extreme conditions. Age and
oxidation cause the bad connections you speak of, not lack of current flow
when the relay closes or opens.

Besides, the technique you describe must take some time to accomplish -
removing the relay for proper service probably wouldn't take any longer.

Mark Z.


Speaker relays should be operated
such that there is enough current flowing at break time to burn off the
contact surface contamination.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/14/03
at 06:39 AM, "Mark D. Zacharias" said:

In many cases it is a residual small dc offset, and/or high-volume
music present when the relay "hits" or when it's disengaged, which
caused the relay problem in the first place.

Unless the offset is high enough to cause some contact heating, I claim
that the offset will tend to prevent or minimize the problem.

Most people turn down the volume before turning off the unit.
Essentially, this is operating the relay in the "dry" region, but it
was never designed to operate there. Speaker relays should be operated
such that there is enough current flowing at break time to burn off the
contact surface contamination. If the relay continually opens without
any significant current to break, it's only a matter of time till the
contact becomes intermittent.

Yes, I can imagine seriously burned contacts becoming a problem, but
I've never observed it. The problem relays I encounter have been
chronically starved for current at break time.

I assumed this fix was for situations where it was impractical to
remove and service the relay.

If it's on the bench anyway, I would simply remove it and service it
properly, assuming that was possible.

Yes, if the customer will pay for it.

Many times they'll call, barely able to communicate this (to them)
bizarre behavior, and I'll have the customer do my procedure at home.
You can argue that I will lose some immediate income, but they will
remember that I treated them well, saved them the bother of a nuisance
service call, and they'll be back later and/or recommend me to their
friends.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

I think you've got it backwards here. High current when the circuit is
broken causes inevitable sparking, thus pitting and carbonization. Sometimes
the contacts actually weld together under extreme conditions. Age and
oxidation cause the bad connections you speak of, not lack of current flow
when the relay closes or opens.

Besides, the technique you describe must take some time to accomplish -
removing the relay for proper service probably wouldn't take any longer.

Mark Z.


Speaker relays should be operated
such that there is enough current flowing at break time to burn off the
contact surface contamination.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/14/03
at 06:39 AM, "Mark D. Zacharias" said:

In many cases it is a residual small dc offset, and/or high-volume
music present when the relay "hits" or when it's disengaged, which
caused the relay problem in the first place.

Unless the offset is high enough to cause some contact heating, I claim
that the offset will tend to prevent or minimize the problem.

Most people turn down the volume before turning off the unit.
Essentially, this is operating the relay in the "dry" region, but it
was never designed to operate there. Speaker relays should be operated
such that there is enough current flowing at break time to burn off the
contact surface contamination. If the relay continually opens without
any significant current to break, it's only a matter of time till the
contact becomes intermittent.

Yes, I can imagine seriously burned contacts becoming a problem, but
I've never observed it. The problem relays I encounter have been
chronically starved for current at break time.

I assumed this fix was for situations where it was impractical to
remove and service the relay.

If it's on the bench anyway, I would simply remove it and service it
properly, assuming that was possible.

Yes, if the customer will pay for it.

Many times they'll call, barely able to communicate this (to them)
bizarre behavior, and I'll have the customer do my procedure at home.
You can argue that I will lose some immediate income, but they will
remember that I treated them well, saved them the bother of a nuisance
service call, and they'll be back later and/or recommend me to their
friends.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/14/03
at 05:49 PM, "Mark D. Zacharias" said:

I think you've got it backwards here. High current when the circuit is
broken causes inevitable sparking,

I want that "sparking". Sparking is what cleans the relay contact. This
type of relay demands a certain amount of arcing to keep the contact
surfaces in good shape. Very low current relays (less than about 5mA)
don't arc and can be gold plated so they won't develop this sort of
problem.

One could use gold plated contacts on speaker relays, but the first
time the customer opens the relay with speaker current flowing, the
gold will be blown away and we'll be stuck with the underlying base
metal contacts. Sometimes relay contacts will be thinly plated with
gold to keep the contacts clean during initial storage, but it is
expected to be blown away after interrupting any significant current.

thus pitting and carbonization.
Sometimes the contacts actually weld together under extreme
conditions. Age and oxidation cause the bad connections you speak of,
not lack of current flow when the relay closes or opens.

Of course, too much arcing will cause damage. Yes, age and oxidation
cause the intermittent contact, but a little arcing will burn the
oxidation off the surface. Some relays are designed to "wipe" (a bit of
rubbing during the make and break) and help scrape the surfaces clean.

I'm sure there are some burnt relay contacts out there. But, even
though I think most consumer amplifiers use wimpy relays, I've never
seen any burned or welded relay contacts on otherwise healthy consumer
amplifiers. The contacts on relays I've opened and cleaned look
perfect.

Besides, the technique you describe must take some time to accomplish
-
removing the relay for proper service probably wouldn't take any
longer.

Assuming the turn-on delay is about 8 seconds, the whole procedure
takes about 4 minutes. The big disadvantage is that your power switch
operating finger or thumb might get tired.

If I've already got the unit open, it is about the same or a little
less time for me to flip the unit over, unsolder one leg of the relay
coil, flash the relay and have it soldered back together. Maybe I'm
slow, but it would take much longer for me to fetch or order a relay,
pull the old one, and insert a new one. Add a bit more time if the unit
is not open. Sometimes one must remove a board or two before the
speaker protection relay is accessible.

For the customer it's a big time saver if they don't even have to take
the unit off the shelf and bring it in.

----

Another failure mode of relays (especially the low current type) is
outgassing of the relay's own case contaminating the contact surface.
(my technique will clear this coating too)

---

I try to promote self help for my customers. About a week ago I had a
very frustrated long time customer call me and start to describe a
wildly intermittant problem with a certain unit. It fit a known pattern
and I have another cute little home cure for that one. I told him what
to do and by the end of our seven minute conversation the unit was
fixed. I bumped into him on the street a few days later -- he's a happy
camper.

You would probably grumble about this trick too, but I started using it
about ten years ago and haven't had any call backs. -- And my little
trick is not nearly as stressful on the unit as disassembling it and
applying the obvious fix. (we also avoid a parts ordering delay)

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/14/03
at 05:49 PM, "Mark D. Zacharias" said:

I think you've got it backwards here. High current when the circuit is
broken causes inevitable sparking,

I want that "sparking". Sparking is what cleans the relay contact. This
type of relay demands a certain amount of arcing to keep the contact
surfaces in good shape. Very low current relays (less than about 5mA)
don't arc and can be gold plated so they won't develop this sort of
problem.

One could use gold plated contacts on speaker relays, but the first
time the customer opens the relay with speaker current flowing, the
gold will be blown away and we'll be stuck with the underlying base
metal contacts. Sometimes relay contacts will be thinly plated with
gold to keep the contacts clean during initial storage, but it is
expected to be blown away after interrupting any significant current.

thus pitting and carbonization.
Sometimes the contacts actually weld together under extreme
conditions. Age and oxidation cause the bad connections you speak of,
not lack of current flow when the relay closes or opens.

Of course, too much arcing will cause damage. Yes, age and oxidation
cause the intermittent contact, but a little arcing will burn the
oxidation off the surface. Some relays are designed to "wipe" (a bit of
rubbing during the make and break) and help scrape the surfaces clean.

I'm sure there are some burnt relay contacts out there. But, even
though I think most consumer amplifiers use wimpy relays, I've never
seen any burned or welded relay contacts on otherwise healthy consumer
amplifiers. The contacts on relays I've opened and cleaned look
perfect.

Besides, the technique you describe must take some time to accomplish
-
removing the relay for proper service probably wouldn't take any
longer.

Assuming the turn-on delay is about 8 seconds, the whole procedure
takes about 4 minutes. The big disadvantage is that your power switch
operating finger or thumb might get tired.

If I've already got the unit open, it is about the same or a little
less time for me to flip the unit over, unsolder one leg of the relay
coil, flash the relay and have it soldered back together. Maybe I'm
slow, but it would take much longer for me to fetch or order a relay,
pull the old one, and insert a new one. Add a bit more time if the unit
is not open. Sometimes one must remove a board or two before the
speaker protection relay is accessible.

For the customer it's a big time saver if they don't even have to take
the unit off the shelf and bring it in.

----

Another failure mode of relays (especially the low current type) is
outgassing of the relay's own case contaminating the contact surface.
(my technique will clear this coating too)

---

I try to promote self help for my customers. About a week ago I had a
very frustrated long time customer call me and start to describe a
wildly intermittant problem with a certain unit. It fit a known pattern
and I have another cute little home cure for that one. I told him what
to do and by the end of our seven minute conversation the unit was
fixed. I bumped into him on the street a few days later -- he's a happy
camper.

You would probably grumble about this trick too, but I started using it
about ten years ago and haven't had any call backs. -- And my little
trick is not nearly as stressful on the unit as disassembling it and
applying the obvious fix. (we also avoid a parts ordering delay)

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/14/03
at 05:49 PM, "Mark D. Zacharias" said:

I think you've got it backwards here. High current when the circuit is
broken causes inevitable sparking,

I want that "sparking". Sparking is what cleans the relay contact. This
type of relay demands a certain amount of arcing to keep the contact
surfaces in good shape. Very low current relays (less than about 5mA)
don't arc and can be gold plated so they won't develop this sort of
problem.

One could use gold plated contacts on speaker relays, but the first
time the customer opens the relay with speaker current flowing, the
gold will be blown away and we'll be stuck with the underlying base
metal contacts. Sometimes relay contacts will be thinly plated with
gold to keep the contacts clean during initial storage, but it is
expected to be blown away after interrupting any significant current.

thus pitting and carbonization.
Sometimes the contacts actually weld together under extreme
conditions. Age and oxidation cause the bad connections you speak of,
not lack of current flow when the relay closes or opens.

Of course, too much arcing will cause damage. Yes, age and oxidation
cause the intermittent contact, but a little arcing will burn the
oxidation off the surface. Some relays are designed to "wipe" (a bit of
rubbing during the make and break) and help scrape the surfaces clean.

I'm sure there are some burnt relay contacts out there. But, even
though I think most consumer amplifiers use wimpy relays, I've never
seen any burned or welded relay contacts on otherwise healthy consumer
amplifiers. The contacts on relays I've opened and cleaned look
perfect.

Besides, the technique you describe must take some time to accomplish
-
removing the relay for proper service probably wouldn't take any
longer.

Assuming the turn-on delay is about 8 seconds, the whole procedure
takes about 4 minutes. The big disadvantage is that your power switch
operating finger or thumb might get tired.

If I've already got the unit open, it is about the same or a little
less time for me to flip the unit over, unsolder one leg of the relay
coil, flash the relay and have it soldered back together. Maybe I'm
slow, but it would take much longer for me to fetch or order a relay,
pull the old one, and insert a new one. Add a bit more time if the unit
is not open. Sometimes one must remove a board or two before the
speaker protection relay is accessible.

For the customer it's a big time saver if they don't even have to take
the unit off the shelf and bring it in.

----

Another failure mode of relays (especially the low current type) is
outgassing of the relay's own case contaminating the contact surface.
(my technique will clear this coating too)

---

I try to promote self help for my customers. About a week ago I had a
very frustrated long time customer call me and start to describe a
wildly intermittant problem with a certain unit. It fit a known pattern
and I have another cute little home cure for that one. I told him what
to do and by the end of our seven minute conversation the unit was
fixed. I bumped into him on the street a few days later -- he's a happy
camper.

You would probably grumble about this trick too, but I started using it
about ten years ago and haven't had any call backs. -- And my little
trick is not nearly as stressful on the unit as disassembling it and
applying the obvious fix. (we also avoid a parts ordering delay)

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

Almost all speaker relays used in consumer equipment use gold-plated
contacts, and have for years.

Additionally, modern surround receivers mostly don't have sound going out
all the various channels during a test procedure on the bench. If the piece
doesn't have 6-ch. inputs, and many don't, then you'll have to mess around
with a mono signal for the center channel, stereo for the left and right
channels, L-R for the surround, at sufficient volume to give you your
desired sparking effect, I presume 30 or so times each. That's up to 90
power on-off cycles, assuming LR front and surround each get one 30-cycle
treatment.
Maybe your finger or thumb WOULD get tired.


Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/14/03
at 05:49 PM, "Mark D. Zacharias" said:

I think you've got it backwards here. High current when the circuit is
broken causes inevitable sparking,

I want that "sparking". Sparking is what cleans the relay contact. This
type of relay demands a certain amount of arcing to keep the contact
surfaces in good shape. Very low current relays (less than about 5mA)
don't arc and can be gold plated so they won't develop this sort of
problem.

One could use gold plated contacts on speaker relays, but the first
time the customer opens the relay with speaker current flowing, the
gold will be blown away and we'll be stuck with the underlying base
metal contacts. Sometimes relay contacts will be thinly plated with
gold to keep the contacts clean during initial storage, but it is
expected to be blown away after interrupting any significant current.

thus pitting and carbonization.
Sometimes the contacts actually weld together under extreme
conditions. Age and oxidation cause the bad connections you speak of,
not lack of current flow when the relay closes or opens.

Of course, too much arcing will cause damage. Yes, age and oxidation
cause the intermittent contact, but a little arcing will burn the
oxidation off the surface. Some relays are designed to "wipe" (a bit of
rubbing during the make and break) and help scrape the surfaces clean.

I'm sure there are some burnt relay contacts out there. But, even
though I think most consumer amplifiers use wimpy relays, I've never
seen any burned or welded relay contacts on otherwise healthy consumer
amplifiers. The contacts on relays I've opened and cleaned look
perfect.

Besides, the technique you describe must take some time to accomplish
-
removing the relay for proper service probably wouldn't take any
longer.

Assuming the turn-on delay is about 8 seconds, the whole procedure
takes about 4 minutes. The big disadvantage is that your power switch
operating finger or thumb might get tired.

If I've already got the unit open, it is about the same or a little
less time for me to flip the unit over, unsolder one leg of the relay
coil, flash the relay and have it soldered back together. Maybe I'm
slow, but it would take much longer for me to fetch or order a relay,
pull the old one, and insert a new one. Add a bit more time if the unit
is not open. Sometimes one must remove a board or two before the
speaker protection relay is accessible.

For the customer it's a big time saver if they don't even have to take
the unit off the shelf and bring it in.

----

Another failure mode of relays (especially the low current type) is
outgassing of the relay's own case contaminating the contact surface.
(my technique will clear this coating too)

---

I try to promote self help for my customers. About a week ago I had a
very frustrated long time customer call me and start to describe a
wildly intermittant problem with a certain unit. It fit a known pattern
and I have another cute little home cure for that one. I told him what
to do and by the end of our seven minute conversation the unit was
fixed. I bumped into him on the street a few days later -- he's a happy
camper.

You would probably grumble about this trick too, but I started using it
about ten years ago and haven't had any call backs. -- And my little
trick is not nearly as stressful on the unit as disassembling it and
applying the obvious fix. (we also avoid a parts ordering delay)

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

Almost all speaker relays used in consumer equipment use gold-plated
contacts, and have for years.

Additionally, modern surround receivers mostly don't have sound going out
all the various channels during a test procedure on the bench. If the piece
doesn't have 6-ch. inputs, and many don't, then you'll have to mess around
with a mono signal for the center channel, stereo for the left and right
channels, L-R for the surround, at sufficient volume to give you your
desired sparking effect, I presume 30 or so times each. That's up to 90
power on-off cycles, assuming LR front and surround each get one 30-cycle
treatment.
Maybe your finger or thumb WOULD get tired.


Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/14/03
at 05:49 PM, "Mark D. Zacharias" said:

I think you've got it backwards here. High current when the circuit is
broken causes inevitable sparking,

I want that "sparking". Sparking is what cleans the relay contact. This
type of relay demands a certain amount of arcing to keep the contact
surfaces in good shape. Very low current relays (less than about 5mA)
don't arc and can be gold plated so they won't develop this sort of
problem.

One could use gold plated contacts on speaker relays, but the first
time the customer opens the relay with speaker current flowing, the
gold will be blown away and we'll be stuck with the underlying base
metal contacts. Sometimes relay contacts will be thinly plated with
gold to keep the contacts clean during initial storage, but it is
expected to be blown away after interrupting any significant current.

thus pitting and carbonization.
Sometimes the contacts actually weld together under extreme
conditions. Age and oxidation cause the bad connections you speak of,
not lack of current flow when the relay closes or opens.

Of course, too much arcing will cause damage. Yes, age and oxidation
cause the intermittent contact, but a little arcing will burn the
oxidation off the surface. Some relays are designed to "wipe" (a bit of
rubbing during the make and break) and help scrape the surfaces clean.

I'm sure there are some burnt relay contacts out there. But, even
though I think most consumer amplifiers use wimpy relays, I've never
seen any burned or welded relay contacts on otherwise healthy consumer
amplifiers. The contacts on relays I've opened and cleaned look
perfect.

Besides, the technique you describe must take some time to accomplish
-
removing the relay for proper service probably wouldn't take any
longer.

Assuming the turn-on delay is about 8 seconds, the whole procedure
takes about 4 minutes. The big disadvantage is that your power switch
operating finger or thumb might get tired.

If I've already got the unit open, it is about the same or a little
less time for me to flip the unit over, unsolder one leg of the relay
coil, flash the relay and have it soldered back together. Maybe I'm
slow, but it would take much longer for me to fetch or order a relay,
pull the old one, and insert a new one. Add a bit more time if the unit
is not open. Sometimes one must remove a board or two before the
speaker protection relay is accessible.

For the customer it's a big time saver if they don't even have to take
the unit off the shelf and bring it in.

----

Another failure mode of relays (especially the low current type) is
outgassing of the relay's own case contaminating the contact surface.
(my technique will clear this coating too)

---

I try to promote self help for my customers. About a week ago I had a
very frustrated long time customer call me and start to describe a
wildly intermittant problem with a certain unit. It fit a known pattern
and I have another cute little home cure for that one. I told him what
to do and by the end of our seven minute conversation the unit was
fixed. I bumped into him on the street a few days later -- he's a happy
camper.

You would probably grumble about this trick too, but I started using it
about ten years ago and haven't had any call backs. -- And my little
trick is not nearly as stressful on the unit as disassembling it and
applying the obvious fix. (we also avoid a parts ordering delay)

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

Almost all speaker relays used in consumer equipment use gold-plated
contacts, and have for years.

Additionally, modern surround receivers mostly don't have sound going out
all the various channels during a test procedure on the bench. If the piece
doesn't have 6-ch. inputs, and many don't, then you'll have to mess around
with a mono signal for the center channel, stereo for the left and right
channels, L-R for the surround, at sufficient volume to give you your
desired sparking effect, I presume 30 or so times each. That's up to 90
power on-off cycles, assuming LR front and surround each get one 30-cycle
treatment.
Maybe your finger or thumb WOULD get tired.


Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Barry Mann" wrote in message
om...
In , on 12/14/03
at 05:49 PM, "Mark D. Zacharias" said:

I think you've got it backwards here. High current when the circuit is
broken causes inevitable sparking,

I want that "sparking". Sparking is what cleans the relay contact. This
type of relay demands a certain amount of arcing to keep the contact
surfaces in good shape. Very low current relays (less than about 5mA)
don't arc and can be gold plated so they won't develop this sort of
problem.

One could use gold plated contacts on speaker relays, but the first
time the customer opens the relay with speaker current flowing, the
gold will be blown away and we'll be stuck with the underlying base
metal contacts. Sometimes relay contacts will be thinly plated with
gold to keep the contacts clean during initial storage, but it is
expected to be blown away after interrupting any significant current.

thus pitting and carbonization.
Sometimes the contacts actually weld together under extreme
conditions. Age and oxidation cause the bad connections you speak of,
not lack of current flow when the relay closes or opens.

Of course, too much arcing will cause damage. Yes, age and oxidation
cause the intermittent contact, but a little arcing will burn the
oxidation off the surface. Some relays are designed to "wipe" (a bit of
rubbing during the make and break) and help scrape the surfaces clean.

I'm sure there are some burnt relay contacts out there. But, even
though I think most consumer amplifiers use wimpy relays, I've never
seen any burned or welded relay contacts on otherwise healthy consumer
amplifiers. The contacts on relays I've opened and cleaned look
perfect.

Besides, the technique you describe must take some time to accomplish
-
removing the relay for proper service probably wouldn't take any
longer.

Assuming the turn-on delay is about 8 seconds, the whole procedure
takes about 4 minutes. The big disadvantage is that your power switch
operating finger or thumb might get tired.

If I've already got the unit open, it is about the same or a little
less time for me to flip the unit over, unsolder one leg of the relay
coil, flash the relay and have it soldered back together. Maybe I'm
slow, but it would take much longer for me to fetch or order a relay,
pull the old one, and insert a new one. Add a bit more time if the unit
is not open. Sometimes one must remove a board or two before the
speaker protection relay is accessible.

For the customer it's a big time saver if they don't even have to take
the unit off the shelf and bring it in.

----

Another failure mode of relays (especially the low current type) is
outgassing of the relay's own case contaminating the contact surface.
(my technique will clear this coating too)

---

I try to promote self help for my customers. About a week ago I had a
very frustrated long time customer call me and start to describe a
wildly intermittant problem with a certain unit. It fit a known pattern
and I have another cute little home cure for that one. I told him what
to do and by the end of our seven minute conversation the unit was
fixed. I bumped into him on the street a few days later -- he's a happy
camper.

You would probably grumble about this trick too, but I started using it
about ten years ago and haven't had any call backs. -- And my little
trick is not nearly as stressful on the unit as disassembling it and
applying the obvious fix. (we also avoid a parts ordering delay)

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

"Barry Mann" wrote in message
om

In , on 12/14/03
at 05:49 PM, "Mark D. Zacharias" said:

I think you've got it backwards here. High current when the circuit
is broken causes inevitable sparking,

I want that "sparking". Sparking is what cleans the relay contact.

Not necessarily. Most relay contacts are designed, if possible to scrub over
each other when they make and break. This does a great job of cleaning the
contact, and is also less damaging than arcing.

This type of relay demands a certain amount of arcing to keep the
contact surfaces in good shape. Very low current relays (less than
about 5mA) don't arc and can be gold plated so they won't develop
this sort of problem.

Agreed, metals like gold, ruthenium, and palladium are used to make or plate
relay contacts that handle low currents (less than 50 milliamps). These are
called "dry circuit" relays. Dry circuit relays are best hermetically sealed
to avoid contamination of the contacts.

Dry circuit relays are sometimes used with a "sealing" DC current that
essentially biases the relay. This is a kind of a kluge and really shouldn't
be necessary with modern relays.

One could use gold plated contacts on speaker relays, but the first
time the customer opens the relay with speaker current flowing, the
gold will be blown away and we'll be stuck with the underlying base
metal contacts.

Also agreed. Relays for power circuits use silver or proprietary alloys
formulated around metals like Tungsten that can take arcing.

In either case, wherever possible, relay contacts are designed to scrub over
each other as they make and break to get a nice self-cleaning action going.

While it all happened over 20 years ago, at the time we did a lot of
research into low and high current relays when we were designing and
building the ABX Comparator. The low-level relays were ruthenium-plated reed
relays, and the high level relays were based on a high temperature
proprietary alloy. I haven't seen that much has changed since then, except
that solid-state devices are far more commonly used to avoid the use of
electromechanical relays.

"Barry Mann" wrote in message
om

In , on 12/14/03
at 05:49 PM, "Mark D. Zacharias" said:

I think you've got it backwards here. High current when the circuit
is broken causes inevitable sparking,

I want that "sparking". Sparking is what cleans the relay contact.

Not necessarily. Most relay contacts are designed, if possible to scrub over
each other when they make and break. This does a great job of cleaning the
contact, and is also less damaging than arcing.

This type of relay demands a certain amount of arcing to keep the
contact surfaces in good shape. Very low current relays (less than
about 5mA) don't arc and can be gold plated so they won't develop
this sort of problem.

Agreed, metals like gold, ruthenium, and palladium are used to make or plate
relay contacts that handle low currents (less than 50 milliamps). These are
called "dry circuit" relays. Dry circuit relays are best hermetically sealed
to avoid contamination of the contacts.

Dry circuit relays are sometimes used with a "sealing" DC current that
essentially biases the relay. This is a kind of a kluge and really shouldn't
be necessary with modern relays.

One could use gold plated contacts on speaker relays, but the first
time the customer opens the relay with speaker current flowing, the
gold will be blown away and we'll be stuck with the underlying base
metal contacts.

Also agreed. Relays for power circuits use silver or proprietary alloys
formulated around metals like Tungsten that can take arcing.

In either case, wherever possible, relay contacts are designed to scrub over
each other as they make and break to get a nice self-cleaning action going.

While it all happened over 20 years ago, at the time we did a lot of
research into low and high current relays when we were designing and
building the ABX Comparator. The low-level relays were ruthenium-plated reed
relays, and the high level relays were based on a high temperature
proprietary alloy. I haven't seen that much has changed since then, except
that solid-state devices are far more commonly used to avoid the use of
electromechanical relays.

"Barry Mann" wrote in message
om

In , on 12/14/03
at 05:49 PM, "Mark D. Zacharias" said:

I think you've got it backwards here. High current when the circuit
is broken causes inevitable sparking,

I want that "sparking". Sparking is what cleans the relay contact.

Not necessarily. Most relay contacts are designed, if possible to scrub over
each other when they make and break. This does a great job of cleaning the
contact, and is also less damaging than arcing.

This type of relay demands a certain amount of arcing to keep the
contact surfaces in good shape. Very low current relays (less than
about 5mA) don't arc and can be gold plated so they won't develop
this sort of problem.

Agreed, metals like gold, ruthenium, and palladium are used to make or plate
relay contacts that handle low currents (less than 50 milliamps). These are
called "dry circuit" relays. Dry circuit relays are best hermetically sealed
to avoid contamination of the contacts.

Dry circuit relays are sometimes used with a "sealing" DC current that
essentially biases the relay. This is a kind of a kluge and really shouldn't
be necessary with modern relays.

One could use gold plated contacts on speaker relays, but the first
time the customer opens the relay with speaker current flowing, the
gold will be blown away and we'll be stuck with the underlying base
metal contacts.

Also agreed. Relays for power circuits use silver or proprietary alloys
formulated around metals like Tungsten that can take arcing.

In either case, wherever possible, relay contacts are designed to scrub over
each other as they make and break to get a nice self-cleaning action going.

While it all happened over 20 years ago, at the time we did a lot of
research into low and high current relays when we were designing and
building the ABX Comparator. The low-level relays were ruthenium-plated reed
relays, and the high level relays were based on a high temperature
proprietary alloy. I haven't seen that much has changed since then, except
that solid-state devices are far more commonly used to avoid the use of
electromechanical relays.

In , on 12/15/03
at 05:53 AM, "Mark D. Zacharias" said:

[ ... ]

Additionally, modern surround receivers mostly don't have sound going
out all the various channels during a test procedure on the bench. If
the piece doesn't have 6-ch. inputs, and many don't, then you'll have
to mess around with a mono signal for the center channel, stereo for
the left and right channels, L-R for the surround, at sufficient
volume to give you your desired sparking effect, I presume 30 or so
times each. That's up to 90 power on-off cycles, assuming LR front and
surround each get one 30-cycle treatment.
Maybe your finger or thumb WOULD get tired.

Not only would your thumb get tired from the power switch, but you'd
have to climb down the test menu again after each power cycle.

A/V receivers are more difficult to deal with on all levels. Access to
the relays is usually very painful. Fortunately, the original poster
complained about the main channels. Some units make my procedure easier
because the Speaker A and Speaker B switches key the protection relays.
Others make things easier because the Mute function keys all the main
room relays. Some recent units (too early for the protection relay
syndrum) have a four or six speaker Stereo mode. And, yes, the six
channel mode can be useful.

Overall, I've had a lot less trouble with the 90's era relays than the
70's and 80's era relays. (Yes, I know, we must be careful evaluating
the data because the 90's relays aren't 20 or more years old.) In the
70's I started seeing relay problems after about five years. In the
late 80's I started seeing better relay choices. The contacts wipe
better and the cases don't degas as much. The poster's unit is one of
the few 90's era relay issues I've come across.

I'm not in bed with this technique. When appropriate, it's a great time
saver.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/15/03
at 05:53 AM, "Mark D. Zacharias" said:

[ ... ]

Additionally, modern surround receivers mostly don't have sound going
out all the various channels during a test procedure on the bench. If
the piece doesn't have 6-ch. inputs, and many don't, then you'll have
to mess around with a mono signal for the center channel, stereo for
the left and right channels, L-R for the surround, at sufficient
volume to give you your desired sparking effect, I presume 30 or so
times each. That's up to 90 power on-off cycles, assuming LR front and
surround each get one 30-cycle treatment.
Maybe your finger or thumb WOULD get tired.

Not only would your thumb get tired from the power switch, but you'd
have to climb down the test menu again after each power cycle.

A/V receivers are more difficult to deal with on all levels. Access to
the relays is usually very painful. Fortunately, the original poster
complained about the main channels. Some units make my procedure easier
because the Speaker A and Speaker B switches key the protection relays.
Others make things easier because the Mute function keys all the main
room relays. Some recent units (too early for the protection relay
syndrum) have a four or six speaker Stereo mode. And, yes, the six
channel mode can be useful.

Overall, I've had a lot less trouble with the 90's era relays than the
70's and 80's era relays. (Yes, I know, we must be careful evaluating
the data because the 90's relays aren't 20 or more years old.) In the
70's I started seeing relay problems after about five years. In the
late 80's I started seeing better relay choices. The contacts wipe
better and the cases don't degas as much. The poster's unit is one of
the few 90's era relay issues I've come across.

I'm not in bed with this technique. When appropriate, it's a great time
saver.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/15/03
at 05:53 AM, "Mark D. Zacharias" said:

[ ... ]

Additionally, modern surround receivers mostly don't have sound going
out all the various channels during a test procedure on the bench. If
the piece doesn't have 6-ch. inputs, and many don't, then you'll have
to mess around with a mono signal for the center channel, stereo for
the left and right channels, L-R for the surround, at sufficient
volume to give you your desired sparking effect, I presume 30 or so
times each. That's up to 90 power on-off cycles, assuming LR front and
surround each get one 30-cycle treatment.
Maybe your finger or thumb WOULD get tired.

Not only would your thumb get tired from the power switch, but you'd
have to climb down the test menu again after each power cycle.

A/V receivers are more difficult to deal with on all levels. Access to
the relays is usually very painful. Fortunately, the original poster
complained about the main channels. Some units make my procedure easier
because the Speaker A and Speaker B switches key the protection relays.
Others make things easier because the Mute function keys all the main
room relays. Some recent units (too early for the protection relay
syndrum) have a four or six speaker Stereo mode. And, yes, the six
channel mode can be useful.

Overall, I've had a lot less trouble with the 90's era relays than the
70's and 80's era relays. (Yes, I know, we must be careful evaluating
the data because the 90's relays aren't 20 or more years old.) In the
70's I started seeing relay problems after about five years. In the
late 80's I started seeing better relay choices. The contacts wipe
better and the cases don't degas as much. The poster's unit is one of
the few 90's era relay issues I've come across.

I'm not in bed with this technique. When appropriate, it's a great time
saver.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------