[Chris F.[_2_]]

I have a Teac Model 80-8 1/2" open reel machine I have to repair for a
customer. This is the first 1/2", 8-track machine I've worked on and it's
clear I'm going to need a schematic. The main problem is that some channels
are sounding through to others; for example, with a signal connected to
channel 1 only, it sounds over to channel 2 and faintly to channel 3. This
happens even when monitoring the input without a tape loaded, ruling out a
head alignment issue.
Any advice, or especially a schematic, would be appreciated.

[Scott Dorsey]

Chris F. wrote:
I have a Teac Model 80-8 1/2" open reel machine I have to repair for a
customer. This is the first 1/2", 8-track machine I've worked on and it's
clear I'm going to need a schematic. The main problem is that some channels
are sounding through to others; for example, with a signal connected to
channel 1 only, it sounds over to channel 2 and faintly to channel 3. This
happens even when monitoring the input without a tape loaded, ruling out a
head alignment issue.
Any advice, or especially a schematic, would be appreciated.

General advice:

1. The full service manual is $20 from Teac. Get it.

2. Every solder joint in the machine is bad. This was some of Teac's first
attempt at wave soldering and these machines are notorious for solder
failures. Budget two or three hours to just go over them all and remelt
them with a little liquid flux.

3. Most control problems like that which are not caused by bad solder joints
are caused by those damn Omron sealed relays. Teac used the cheap alloy
contact ones, and the contacts gunk up. Pre-emptive replacement with the
silver contact ones is recommended.

4. Change the pinch roller while it's on the bench.

5. Equalization is IEC. God help you if you have only the standard NAB
alignment tape. You can do it by using fudge factors on the tones and
MRL will send you directions on how, but it's no fun at all to do.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Mike Rivers]

On 1/22/2011 9:47 PM, Chris F. wrote:

This is the first 1/2", 8-track machine I've worked on and it's
clear I'm going to need a schematic. The main problem is that some channels
are sounding through to others; for example, with a signal connected to
channel 1 only, it sounds over to channel 2 and faintly to channel 3. This
happens even when monitoring the input without a tape loaded, ruling out a
head alignment issue.

But what it doesn't leave out is crosstalk at the record
head when you're monitoring in the Sync mode. The record
head acts as a transformer, coupling the Channel 1 signal to
Channel 2, which you hear since Channel 2, when not in Input
Monitor mode, is in the playback mode, but playing back off
the record head.

Put it in All Input Monitor mode and see if that problem
goes away. This is a common issue with half- and
quarter-width tracks.

It's true that the machine might need a good going-over,
but as I recall, the head alignment is fixed, and the EQ and
bias controls have a pretty small range (intentionally) so
that someone who doesn't know what he's doing can't screw it
up too badly. You'll need an IEC alignment tape in order to
get the low frequency response correct.

The original owner's manual had a full schematic (ahhh!
Those were the days!) so ask the owner if he has the manual.
TASCAM is pretty good with old owner's manuals, but that was
the day before all of these things were produced on
computer, so they'll probably have to copy it page by page
if they no longer have any printed copies in stock, and that
might cost more than the $20 that Scott suggested.


--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[Chris F.[_2_]]

But what it doesn't leave out is crosstalk at the record head when you're
monitoring in the Sync mode. The record head acts as a transformer,
coupling the Channel 1 signal to Channel 2, which you hear since Channel
2, when not in Input Monitor mode, is in the playback mode, but playing
back off the record head.

Put it in All Input Monitor mode and see if that problem goes away. This
is a common issue with half- and quarter-width tracks.

So would this mean the head is defective, or would it be something like the
relays that Scott mentioned?

[Scott Dorsey]

Mike Rivers wrote:
It's true that the machine might need a good going-over,
but as I recall, the head alignment is fixed, and the EQ and
bias controls have a pretty small range (intentionally) so
that someone who doesn't know what he's doing can't screw it
up too badly. You'll need an IEC alignment tape in order to
get the low frequency response correct.

The head alignment CAN be adjusted with shims, like that of the Scully 100.
You really don't ever, ever want to have to do that so hope it's not too
far off.

The bias and gain settings basically allow you to adjust for any given
batch of Ampex 406 tape, and they won't go any farther than that. RMGI
is now selling SM911, a tape whose bias level is deliberately very close
to that of 456. I am pretty sure it can be set up on an 80-8 but you
won't be sure until you see it on the scope.

But I'm willing to bet that the original poster's problem is a bad ground
somewhere, probably due to a cold joint. If it's not, then that will be
the _next_ problem he'll encounter.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Chris F. wrote:
But what it doesn't leave out is crosstalk at the record head when you're
monitoring in the Sync mode. The record head acts as a transformer,
coupling the Channel 1 signal to Channel 2, which you hear since Channel
2, when not in Input Monitor mode, is in the playback mode, but playing
back off the record head.

Put it in All Input Monitor mode and see if that problem goes away. This
is a common issue with half- and quarter-width tracks.

So would this mean the head is defective, or would it be something like the
relays that Scott mentioned?

No, it's just the way narrowtrack machines are. They all have crosstalk
because they're trying to jam too damn many tracks onto a little piece of
tape.

This is one of the reasons why standard 8-track machines used 1" tape.

But, if it's really, really bad, look for bad solder joints and bad decoupling
caps.

Normal crosstalk will be reasonably high between adjacent tracks but not
noticeable at all between tracks 1 and 8. If you hear crosstalk between
1 and 8, there's a problem.

Note also that when you set it up, you will never be able to get the response
on the edge tracks flat; they will always droop a bit on the high end. Put
kick drum and bass on 1 and 8....
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Chris F.[_2_]]

3. Most control problems like that which are not caused by bad solder
joints
are caused by those damn Omron sealed relays. Teac used the cheap alloy
contact ones, and the contacts gunk up. Pre-emptive replacement with
the
silver contact ones is recommended.

Replacing the relays is a bit too expensive - they retail for about $50
apiece, and there are at least 16 of them in this unit.

Does anyone know where I could obtain a proper test tape for this? The
manual specifies YTT-1144.

[Scott Dorsey]

Chris F. wrote:
3. Most control problems like that which are not caused by bad solder
joints
are caused by those damn Omron sealed relays. Teac used the cheap alloy
contact ones, and the contacts gunk up. Pre-emptive replacement with
the
silver contact ones is recommended.

Replacing the relays is a bit too expensive - they retail for about $50
apiece, and there are at least 16 of them in this unit.

Yes. Life is like that. Welcome to the world of disposable consumer
electronics.

They should be a good bit less than $50, though, since they are standard
Omron items.

Does anyone know where I could obtain a proper test tape for this? The
manual specifies YTT-1144.

MRL will sell you one. In a pinch you can use any regular NAB MRL tape
and the fudge factors but they can cut you a special IEC one on request.
Depending on your hourly rate getting the IEC one may be a cost saving.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[gtbuba]

On Jan 23, 3:58*pm, (Scott Dorsey) wrote:
Chris F. wrote:
3. Most control problems like that which are not caused by bad solder
joints
* are caused by those damn Omron sealed relays. *Teac used the cheap alloy
* contact ones, and the contacts gunk up. *Pre-emptive replacement with
the
* silver contact ones is recommended.

Replacing the relays is a bit too expensive - they retail for about $50
apiece, and there are at least 16 of them in this unit.

Yes. *Life is like that. *Welcome to the world of disposable consumer
electronics.

They should be a good bit less than $50, though, since they are standard
Omron items. *

Does anyone know where I could obtain a proper test tape for this? The
manual specifies YTT-1144.

MRL will sell you one. *In a pinch you can use any regular NAB MRL tape
and the fudge factors but they can cut you a special IEC one on request.
Depending on your hourly rate getting the IEC one may be a cost saving.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

I used one with the dbx noise reduction 1980-1987. Not long after we
bought a studio including the machine it needed new heads. I couldn't
get two channels to sound the same until the new heads were put in. I
could snap tape with this machine if not being careful . GT.

[Mike Rivers]

On 1/23/2011 10:52 AM, Chris F. wrote:

Put it in All Input Monitor mode and see if that problem goes away. This
is a common issue with half- and quarter-width tracks.

So would this mean the head is defective, or would it be something like the
relays that Scott mentioned?

Neither. It's inherent in the design of a narrow track head.
Even on 2" 16 track machines, we learned how to deal with
the same problem, putting time code on one of the edge
tracks and leaving an empty track adjacent to it, or worst
case, putting a track next to the time code track that could
wouldn't suffer much with EQ to get rid of the leakage from
the time code.

This is one of the problems that digital recording (whether
on tape or in a computer) made go away.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[Scott Dorsey]

gtbuba wrote:

I used one with the dbx noise reduction 1980-1987. Not long after we
bought a studio including the machine it needed new heads. I couldn't
get two channels to sound the same until the new heads were put in. I
could snap tape with this machine if not being careful . GT.

Sounds like your tension may have been set a touch high there...
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Peter Larsen[_3_]]

Mike Rivers wrote:

This is one of the problems that digital recording (whether
on tape or in a computer) made go away.

In some ways analog tape technology is unbelievably poor and it is beyond
belief that so much quality sound has been recorded with it.

Kind regards

Peter Larsen

[Scott Dorsey]

Peter Larsen wrote:
Mike Rivers wrote:

This is one of the problems that digital recording (whether
on tape or in a computer) made go away.

In some ways analog tape technology is unbelievably poor and it is beyond
belief that so much quality sound has been recorded with it.

That, in great part, has to do with many decades of technological advancement
and very careful manufacture and operation by a whole lot of people.

That said.... narrowtrack consumer recorders like the 80-8 are not a good
example of what is possible with analogue recording technology, any more
than the Compact Cassette is.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[[email protected]]

On 2011-01-24 said:
Mike Rivers wrote:
This is one of the problems that digital recording (whether
on tape or in a computer) made go away.
In some ways analog tape technology is unbelievably poor and it is
beyond belief that so much quality sound has been recorded with it.

True, but when you've got quality sound going into the
microphones makes it a bit easier, even through the
shortcomings. wHo cares about the bleed if the performance
is good, and you learn how to use it to your advantage?





Richard webb,

replace anything before at with elspider
ON site audio in the southland: see www.gatasound.com

[Chris F.[_2_]]

After a bit of troubleshooting, I've come to the conclusion that the
record/playback head is defective. I checked all the heads for continuity
and shorts, and found that channel 3 of the R/P head is shorting to the
chassis ground. I've never seen this type of head failure before, but
testing seems to confirm it - the short appears even with the head leads
unsoldered from the terminal strip above. I'm assuming the only fix for this
is to replace the head. However, I cannot locate one or even find a
reference to it. The part number on the head is 53783005. Is there another
part number that might be equivalent, or is my customer just plain out of
luck?


"Chris F." wrote in message
...
I have a Teac Model 80-8 1/2" open reel machine I have to repair for a
customer. This is the first 1/2", 8-track machine I've worked on and it's
clear I'm going to need a schematic. The main problem is that some
channels are sounding through to others; for example, with a signal
connected to channel 1 only, it sounds over to channel 2 and faintly to
channel 3. This happens even when monitoring the input without a tape
loaded, ruling out a head alignment issue.
Any advice, or especially a schematic, would be appreciated.

[Scott Dorsey]

Chris F. wrote:
After a bit of troubleshooting, I've come to the conclusion that the
record/playback head is defective. I checked all the heads for continuity
and shorts, and found that channel 3 of the R/P head is shorting to the
chassis ground. I've never seen this type of head failure before, but
testing seems to confirm it - the short appears even with the head leads
unsoldered from the terminal strip above. I'm assuming the only fix for this
is to replace the head. However, I cannot locate one or even find a
reference to it. The part number on the head is 53783005. Is there another
part number that might be equivalent, or is my customer just plain out of
luck?

Call JRF Magnetics, they will possibly have a sub. Expect to pay between
five and ten times the value of the machine for a replacement, though.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Rick Ruskin]

On 26 Jan 2011 11:41:08 -0500, (Scott Dorsey) wrote:

Chris F. wrote:
After a bit of troubleshooting, I've come to the conclusion that the
record/playback head is defective. I checked all the heads for continuity
and shorts, and found that channel 3 of the R/P head is shorting to the
chassis ground. I've never seen this type of head failure before, but
testing seems to confirm it - the short appears even with the head leads
unsoldered from the terminal strip above. I'm assuming the only fix for this
is to replace the head. However, I cannot locate one or even find a
reference to it. The part number on the head is 53783005. Is there another
part number that might be equivalent, or is my customer just plain out of
luck?

Call JRF Magnetics, they will possibly have a sub. Expect to pay between
five and ten times the value of the machine for a replacement, though.
--scott


Or swap the ther r/p and play heads around and use it as a 2-head
machine. They 2 heads are identical. The play head on the 80-8 and
all later TACAM multi-tracks was there for alignment. Once all
heads/electronics agreed, all work was to be done from the r/p head.
Rick Ruskin
Lion Dog Music - Seattle WA
http://liondogmusic.com
http://www.myspace.com/rickruskin

[Mike Rivers]

On 1/26/2011 11:22 AM, Chris F. wrote:
After a bit of troubleshooting, I've come to the conclusion that the
record/playback head is defective.

Check with John French at JRF Magnetic Sciences. He may have
a replacement or may be able to repair the head. It would
probably be best to send him the whole head assembly so he
can check it all out and, if he can do anything for you, get
it all in alignment. He can do some impossible sounding
stuff when it comes to fixing heads.

http://jrfmagnetics.com/


--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[Chris F.[_2_]]

Or swap the ther r/p and play heads around and use it as a 2-head
machine. They 2 heads are identical. The play head on the 80-8 and
all later TACAM multi-tracks was there for alignment. Once all
heads/electronics agreed, all work was to be done from the r/p head.

The r/p and playback heads are not the same, the playback head is a bit
narrower and has a different part number. It's worth noting, though, that
the r/p head does not appear to be original, so there's a chance that part
number may not be correct.
I see an r/p head from a model 70-8 for sale on eBay.... the part number
is different, but I wonder if it would work?

[Rick Ruskin]

On Wed, 26 Jan 2011 11:48:47 -0800, "Chris F."
wrote:


Or swap the ther r/p and play heads around and use it as a 2-head
machine. They 2 heads are identical. The play head on the 80-8 and
all later TACAM multi-tracks was there for alignment. Once all
heads/electronics agreed, all work was to be done from the r/p head.

The r/p and playback heads are not the same, the playback head is a bit
narrower and has a different part number. It's worth noting, though, that
the r/p head does not appear to be original, so there's a chance that part
number may not be correct.
I see an r/p head from a model 70-8 for sale on eBay.... the part number
is different, but I wonder if it would work?



They are supposed to be the same on the 80-8 and all machines that
followed.

I wouldn't consider using a 70 series head on an 80-8. The 70 series
r/p head is not at all the same. Plus, those machines had very poor
sync response compared to the playback head.


Rick Ruskin
Lion Dog Music - Seattle WA
http://liondogmusic.com
http://www.myspace.com/rickruskin

[William Sommerwerck]

They are supposed to be the same on the 80-8
and all machines that followed.

At 15ips, even HF wavelengths are "long enough" that one could get away
using a record head for playback. That was the theory, anyway.

[Chris F.[_2_]]

I think I have a plan figured out. Since the heads are interchangeable, I
will go ahead and swap them. Then, since I won't be able to calibrate
channel 3 properly, I might try this: I'll align the other channels, then
swap one of those cards with the channel 3 card. I'm assuming each card,
once calibrated, would have the adjustments set at very similar positions.
In the end, track 3 may not be 100% properly calibrated, but I'm guessing it
would be close enough that nobody could tell. This way, I could save the
customer the extra time and expense of replacing the head (and have my
workbench freed up that much sooner).

"William Sommerwerck" wrote in message
...
They are supposed to be the same on the 80-8
and all machines that followed.

At 15ips, even HF wavelengths are "long enough" that one could get away
using a record head for playback. That was the theory, anyway.

[Chris F.[_2_]]

Call JRF before you do anything. He may just have a spare head sitting
around.

I did. He had one, and wants $315 for it. My customer is already looking
at $175 for a test tape and at least $200 for my labor, so I don't think
he's going to want to spend another $315+ just to gain the ability to
calibrate track 3.

[Mike Rivers]

On 1/27/2011 11:06 AM, Chris F. wrote:
I did. He had one, and wants $315 for it. My customer is already looking
at $175 for a test tape and at least $200 for my labor, so I don't think
he's going to want to spend another $315+ just to gain the ability to
calibrate track 3.

Cordially welcome him to the world of analog recording, sort of. But try
what Rick suggested about swapping the play and record heads. I didn't
think of that, but it might solve your problem. Though I think (if I'm
thinking of the right thread here) it won't solve the crosstalk issue
since that's inherent in the head.

--
"Today's production equipment is IT based and cannot be operated without
a passing knowledge of computing, although it seems that it can be
operated without a passing knowledge of audio" - John Watkinson

Drop by http://mikeriversaudio.wordpress.com now and then

[Peter Larsen[_3_]]

Chris F. wrote:

Call JRF before you do anything. He may just have a spare head
sitting around.

I did. He had one, and wants $315 for it.

No, he wants USD 315 for it AND for the shelf space it has been on AND for
the wisdom to put on on said shelf.


Kind regards

Peter Larsen

[Peter Larsen[_3_]]

Chris F. wrote:

Call JRF before you do anything. He may just have a spare head
sitting around.

I did. He had one, and wants $315 for it. My customer is already
looking at $175 for a test tape and at least $200 for my labor, so I
don't think he's going to want to spend another $315+ just to gain
the ability to calibrate track 3.

Wanting to use analog tape for sound recording is kinda like wanting to
commute in a White Steamer.


Kind regards

Peter Larsen

[Scott Dorsey]

Peter Larsen wrote:
Chris F. wrote:

Call JRF before you do anything. He may just have a spare head
sitting around.

I did. He had one, and wants $315 for it. My customer is already
looking at $175 for a test tape and at least $200 for my labor, so I
don't think he's going to want to spend another $315+ just to gain
the ability to calibrate track 3.

Wanting to use analog tape for sound recording is kinda like wanting to
commute in a White Steamer.

I disagree.

But then again, I am commuting in a 1974 BMW. I wouldn't mind trying the
White Steamer although I'd rather have a Bearcat.

However, let me make an important distinction here. Professional analogue
tape is one thing, but narrowtrack analogue tape is a very different thing.
I think there are good reasons to use analogue tape, but I do not think they
extend to narrowtrack formats.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Peter Larsen[_3_]]

Scott Dorsey wrote:

Wanting to use analog tape for sound recording is kinda like wanting
to commute in a White Steamer.

I disagree.

But then again, I am commuting in a 1974 BMW. I wouldn't mind trying
the White Steamer although I'd rather have a Bearcat.

The comparion is not about drive quality, it is about expectable driving
expenses. See also the quality point below.

However, let me make an important distinction here. Professional
analogue tape is one thing, but narrowtrack analogue tape is a very
different thing. I think there are good reasons to use analogue tape,
but I do not think they extend to narrowtrack formats.

I seriously think a late-version White Steamer is quite possibly the best
motorcar ever, with DS19/21 as runner-up. I am also quite aware of my
surprise over not hearing the noise from the tape on the tape flanges when
listening to high sample rate digital.

--scott

Kind regards

Peter Larsen

[Scott Dorsey]

Peter Larsen wrote:
Scott Dorsey wrote:

Wanting to use analog tape for sound recording is kinda like wanting
to commute in a White Steamer.

I disagree.

But then again, I am commuting in a 1974 BMW. I wouldn't mind trying
the White Steamer although I'd rather have a Bearcat.

The comparion is not about drive quality, it is about expectable driving
expenses. See also the quality point below.

Excellent point, then. In many cases the money is going the same place, too.
When your manual tells you regrease bearings every 500 miles, or it tells
you to do an azimuth check every morning, it puts a considerable amount of
extra overhead on the user. You can hire a chauffeur or a tape op, or you
can bite the bullet and learn to do it yourself.

I seriously think a late-version White Steamer is quite possibly the best
motorcar ever, with DS19/21 as runner-up. I am also quite aware of my
surprise over not hearing the noise from the tape on the tape flanges when
listening to high sample rate digital.

You need a DASH machine, then! Plenty of tape flange noise!

The cost of analogue recorders is artificially low today; you could not make
a new machine for anything approaching what Mike Spitz is selling refurb
ATR-100s for, let alone for the $250 or so that a used 440B will set you
back.

But, the cost of the media is higher than it used to be, due to smaller
sized production runs and the fact that the cheaper grade media are no longer
available. When Ampex was making millions of reels of 406 and 456, low
end users could order a case of 031 "reject grade" tape for a couple dollars
a reel. Now RMGI is making thousands, not millions, and prices are higher.

And, the cost of maintenance is higher than it used to be, partly because
there are fewer people doing the work and partly because so many of the
people who worked in the broadcast industry found they could make a lot
more money for a lot less effort fixing computers. So they expect more
for their labour, and there is less of it available.

On top of this, studios often have no technical staff, what with the move
to smaller and home studios.

This has resulted in an interesting situation where people buy tape machines
and cannot afford to operate them.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."