Re: Rock ola 474 amp

On 2020/08/10 12:37 p.m., Dave N. wrote:
> I just pick up two Rockola 474's and the one I'm working on has static
> in the right speaker all the time sometimes you can hear it over the
> music. I have replaced most all of the electrolytic capacitors on the
> driver board, the pre amp and the power board with no change in the
> noise. has any one ever had this before.
> 
> Thank you for your help
> 
> Dave Niccum
> Georgetown, Il USA
> 
> 
> 
> 

Unlikely to be a capacitor, more likely a resistor or transistor or even 
a noisy electrical connection.

First, try unplugging the input to the amp. If that solves the noise 
then check the cartridge and wiring.

When you adjust the volume does the noise go up/down with it?

If yes, then the problem is either the volume control or in the pre-amp.

If it doesn't change then the problem is most likely in the power amp 
section.

An audio signal tracer is what you want to track that down!

John :-#)#

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