recently i acquired a fisher 400 tube receiver in great condition , all
tubes light etc but no sound at all anyone give me advice on what to check
email me at

In article , Hydebee wrote:
recently i acquired a fisher 400 tube receiver in great condition , all
tubes light etc but no sound at all anyone give me advice on what to check
email me at

Well, I'd start checking out the B+ and making sure the rectifier tube is
good, then working my way through the output stage. These things are basically
very easy to work on and your local TV repair shop should be able to deal
with it. They have a couple odd things here and there (like filaments being
used as cathode resistors) but for the most part they are straightforward
and docs are easy to get.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 3/30/05 10:07 PM, in article , "Scott
Dorsey" wrote:

... They have a couple odd things here and there (like filaments being
used as cathode resistors)

???!
THAT¹S interesting...

In article writes:

... They have a couple odd things here and there (like filaments being
used as cathode resistors)

???! THAT'S interesting...

This wasn't all that uncommon. It saved a part and got DC on the
filaments of tubes in applications where AC on the filaments might
introduce hum. But it means that when the filament opens up, you have
two problems - the tube failure and the failure of the circuit
depending on it for proper bias. And vice versa.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

SSJVCmag wrote:
On 3/30/05 10:07 PM, in article , "Scott
Dorsey" wrote:

... They have a couple odd things here and there (like filaments being
used as cathode resistors)

???!
THAT¹S interesting...

I'm not sure why Fisher did it. The same trick is also used on some
phantom-powered mikes using submini tubes, and I know it was done there
for efficiency.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey wrote:
SSJVCmag wrote:
On 3/30/05 10:07 PM, in article ,
"Scott
Dorsey" wrote:

... They have a couple odd things here and there (like filaments
being
used as cathode resistors)

???!
THAT=B9S interesting...

I'm not sure why Fisher did it. The same trick is also used on some
phantom-powered mikes using submini tubes, and I know it was done
there
for efficiency.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."


I think because they wanted to run the filaments on DC to reduce hum
and it was not easy in those days before transistors and silicon
diodes to build a low volatge realtivly high current DC power supply
that is well filtered. It took big caps and or inductors.

Mark