won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately, otherwise with the 6ca4 pulled out all the other
tubes (12ax7 etc.) in it power up and the tubes light up, could the
fix be as simple as replacing the 6ca4?

won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately,


** A shorted rectifier will blow the fuse at switch on.





.......... Phil

if you still want to use a tube
and you have no 6CA4 you could use a
6V4 in some amps

wrote in message
oups.com...
won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately, otherwise with the 6ca4 pulled out all the other
tubes (12ax7 etc.) in it power up and the tubes light up, could the
fix be as simple as replacing the 6ca4?

It happened to me with a 5V4G, but it began sparking like hell only as soon
as it became hot enough to conduce some current. It was CLEARLY visible.
But, before risking a good new tube, I'd check for a shorted capacitor or
even (it happens, trust me) for some f%!!#!ing ant fried among anode pins
and chassis.

Ciao

Fabio


"Phil Allison" ha scritto nel messaggio
...


won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately,


** A shorted rectifier will blow the fuse at switch on.





......... Phil

"Fabio Berutti"

** Stop top posting - you dumb wog !




"Phil Allison"


won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately,


** A shorted rectifier will blow the fuse at switch on.


............ Phil


It happened to me with a 5V4G, but it began sparking like hell only as
soon as it became hot enough to conduce some current. It was CLEARLY
visible. But, before risking a good new tube, I'd check for a shorted
capacitor or even (it happens, trust me) for some f%!!#!ing ant fried
among anode pins and chassis.


** A shorted filter cap would not blow a fuse until the rectifier heated up.

An insect shorting an anode pin to chassis would not care if the tube was
fitted.




........... Phil

in article ,
at wrote on 7/27/05 4:01 AM:

won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately, otherwise with the 6ca4 pulled out all the other
tubes (12ax7 etc.) in it power up and the tubes light up, could the
fix be as simple as replacing the 6ca4?

When you pulled out the rectifier, you disconnected the high voltage from
the circuit.

You probably have a shorted filter capacitor, which is drawing too much
current through the rectifier and blowing the fuse.

"Phil Allison" ha scritto nel messaggio
...

"Fabio Berutti"

** Stop top posting - you dumb wog !




"Phil Allison"


won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately,


** A shorted rectifier will blow the fuse at switch on.


............ Phil


It happened to me with a 5V4G, but it began sparking like hell only as
soon as it became hot enough to conduce some current. It was CLEARLY
visible. But, before risking a good new tube, I'd check for a shorted
capacitor or even (it happens, trust me) for some f%!!#!ing ant fried
among anode pins and chassis.


** A shorted filter cap would not blow a fuse until the rectifier heated
up.

An insect shorting an anode pin to chassis would not care if the tube was
fitted.


unless it is a power tube anode... no rectifier, no B+, no shorts will
happen anywhere but in the filament circuit...
It is unclear if the fuse blows immediately or as soon as the 6CA4 heats up
a bit, but most of the cooked fuses I got were due to unbelievably stupid
problems, pure Murphy's law.

Salam'aleikum

Fabio





.......... Phil

It is unclear if the fuse blows immediately or as
soon as the 6CA4 heats up
a bit

if the 6ca4 is the only tube plugged in the fuse blows immediately when
the unit is turned on

if all the other tubes are plugged in and the 6ca4 is not plugged in
the fuse does not blow when the unit is turned on and the tubes light up

said:

if the 6ca4 is the only tube plugged in the fuse blows immediately when
the unit is turned on


It is possible that the 6CA4 (EZ81) developed a short between
electrodes, presumably the heater and one of the anodes.
You can replace the tube, or use 2 1N4007 silicon diodes with series
resistors of about 47 ohm/5 watts instead.

I suspect the supply caps will be OK, since the fuse blows
immediately. If they weren't, the fuse would only blow after warming
up of the 6CA4.

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

in article , Sander deWaal at
wrote on 7/27/05 2:29 PM:

said:

if the 6ca4 is the only tube plugged in the fuse blows immediately when
the unit is turned on


It is possible that the 6CA4 (EZ81) developed a short between
electrodes, presumably the heater and one of the anodes.
You can replace the tube, or use 2 1N4007 silicon diodes with series
resistors of about 47 ohm/5 watts instead.

I suspect the supply caps will be OK, since the fuse blows
immediately. If they weren't, the fuse would only blow after warming
up of the 6CA4.


Your reasoning is correct; mine was not. Mea culpa!

Jon

wrote:
won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately, otherwise with the 6ca4 pulled out all the other
tubes (12ax7 etc.) in it power up and the tubes light up, could the
fix be as simple as replacing the 6ca4?

The filter electrolytic cap is probably shorted. Be happy
the equipment had a fuse, power transformers are
expensive to replace.

"robert casey"


won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately, otherwise with the 6ca4 pulled out all the other
tubes (12ax7 etc.) in it power up and the tubes light up, could the
fix be as simple as replacing the 6ca4?

The filter electrolytic cap is probably shorted. Be happy
the equipment had a fuse, power transformers are
expensive to replace.



** Robert - do you EVER ****ing get anything right ???

I am getting heartily sick of having to post corrections to all the
erroneous bull**** you post on usenet !!




........... Phil

first thing is to check the rectifier tube for shorts. obvious shorts
would appear even with an ohm meter out of circuit. ( its 99% chance
that its bad.) since you have the tube pulled, check for other shorts
on the high voltag side to make sure that when you change it you don't
exceed the 150mA of current that the tube can handle (typically). Caps
can go bad if a cathode to plate short happens, especially if the
filter caps are polarized electrolytics. Oil bath caps are more
"forgiving" about this senareo. Also you might want to take your
output tube(s) out and check them for leakage, shorts, ect with a tube
checker as something most likely caused the event to happen. Also you
might want mesure the current on the high volage once you get it going
to make sure you got all the bugs out of it.

** Robert - do you EVER get anything right ???


It occasionally happens :-)

But okay, the 6CA4 is an indirectly heated cathode tube,
thought it was directly heated... duh.
But a lot of other posters also made the same error....

"robert casey"


** Robert - do you EVER get anything right ???


It occasionally happens :-)

But okay, the 6CA4 is an indirectly heated cathode tube,
thought it was directly heated... duh.
But a lot of other posters also made the same error....


** Nothing to do with it !!!

You just keep making more and worse errors.

Better go re-read the whole thread.



........... Phil

Fabio Berutti wrote:
"Phil Allison" ha scritto nel messaggio
...

"Fabio Berutti"

** Stop top posting - you dumb wog !





"Phil Allison"



won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately,


** A shorted rectifier will blow the fuse at switch on.


............ Phil

It happened to me with a 5V4G, but it began sparking like hell only as
soon as it became hot enough to conduce some current. It was CLEARLY
visible. But, before risking a good new tube, I'd check for a shorted
capacitor or even (it happens, trust me) for some f%!!#!ing ant fried
among anode pins and chassis.


** A shorted filter cap would not blow a fuse until the rectifier heated
up.

An insect shorting an anode pin to chassis would not care if the tube was
fitted.



unless it is a power tube anode... no rectifier, no B+, no shorts will
happen anywhere but in the filament circuit...
It is unclear if the fuse blows immediately or as soon as the 6CA4 heats up
a bit, but most of the cooked fuses I got were due to unbelievably stupid
problems, pure Murphy's law.

Salam'aleikum

Fabio



A friend brought me a Bell 6060 once because it was blowing fuses,even
with the tubes pulled.
Upon inspection,I had found a filament wire that had rubbed through the
insulation,right where it comes out from the trany's end-bell.Usually
might not have been a big problem,except the filament winding was
center-tapped,and grounded.
A nice layer or two of electrical tape fixed that up for him.I would
have just replaced the old wiring,but the tranny was a PITA to get
apart,and it woulda been a major hassle.Besides the filament wiring is
at a low potential.(If it were HV B+ wiring,it woulda been replaced!)

wrote

if the 6ca4 is the only tube plugged in the fuse blows immediately
when
the unit is turned on

if all the other tubes are plugged in and the 6ca4 is not plugged
in
the fuse does not blow when the unit is turned on and the tubes
light up

Could be a fried ant stuck between the rectifier pins.

cheers, Ian

wrote:
won't work, when the 6ca4 power/rectifier tube is in it, it blows the
fuse immediately, otherwise with the 6ca4 pulled out all the other
tubes (12ax7 etc.) in it power up and the tubes light up, could the
fix be as simple as replacing the 6ca4?



If the fuse blows IMMEDIATELY at turnon, then a shorted 6CA4 is the
likely culprit.

If the fuse only blows once the 6CA4 has a chance to warm up, then I
would check the filter capacitors and output tubes for shorts.


Bob Weiss N2IXK