[R-390] Popping noise problem

[Claudio Spiritelli]

Joe,

Yes I did change the capacitor as well as I did change all the capacitors
around the limiter (C549,C532,C536,C531)  the only one I did not change yet
is C537. I am convinced that the noise is generated on this section , as a
matter of fact even without C531 and C549 ( section completely isolated)
the noise persist since I can see it on the plate (pin1) of V507 with  the
scope, this test should also eliminate the suggestion from James ( coax
cables to the Diode Load). I am afraid that the problem is on the socket of
V507. Is this possible?
Or should a pay attention to the resistors as well? or am I overlooking
something?

Thanks to all
Claudio Spiritelli



-----Original Message-----
From: Joe Foley [mailto:redmenaced@yahoo.com]
Sent: Sunday, January 27, 2002 7:25 PM
To: Claudio Spiritelli
Subject: Re: [R-390] Popping noise problem





>
> When I turn the limiter on, the noise disappear on
> the audio as well as I do
> not see it with the scope and the B+ line does not
> have any low frequency
> variation. That made me to believe that the
> capacitor C536 was the cause.
> Wrong.
+++++++++
That's what I would suspect, too.

Why do you think the capacitor is good?

Did you test it at its rated voltage and check to see
what the leakage current is?

How old is the capacitor?

Try changing it anyway and see if the noise goes away.
 In an old radio ALL caps are suspect!

Joe

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