Vintage Synth Repair

I would argue against replacing the caps as the stages of the amp are  
all DC coupled withe exception
of C601, the 1 uf coupling cap at tyhe input staGE. My money( we are  
all guessing here) is on the input differential
stage as the culprit, specifically TR601,that's the 5 legged dual  
transistor. 2SC2259?
if you are just determined to replace caps, try c601 first.
On Aug 1, 2009, at 10:44 PM, rpcfender wrote:

> I have a Fostex Model 600 power amp.
> A while ago one of the channels started to quietly pop and click.
> I pulled the 1/4inch jack (from my mixer) in and out and it cleared  
> up (the plug socket is not switched) so I thought it was a dirty  
> contact.
> The problem returned and was fixed several times.
>
> Now the pops and clicks are intermittent and the replugging has no  
> effect.
>
> It doesn't seem thermal because if it is left alone with just the  
> quiescent current flowing though it, it can start noisy then it can  
> be quiet for and hour and the pops just start up again.
> The DC measurements are close to the cct diagram.
>
> Before I start replacing all the caps, should I be looking at some  
> other components?
>
> Thanks
>
> Royce
>
>
>
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