JCM 800 Strange noise and master volume acting up

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Hawksey93
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JCM 800 Strange noise and master volume acting up

Post by Hawksey93 » Thu Mar 25, 2021 3:51 pm

Hey Guys

After retubing, recapping and biassing my 1986 JCM800 2203 I’m having a couple of issues

When I turn the amp on after letting it warm up I’m getting a strange scratching noise which goes away after a few minutes, I’m also getting what seems like a grounding issue when I touch the pots. Also, the master volume pot does not mute the amp when it’s all the way down, it’s only fully muted when the pre-amp pot is down

I’ve got the chassis open and have DMM on hand, could anyone assist me in tracking down the cause of these issues please?

Thanks a lot

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