Hi, I've got a Marshall AVT-50 head I want to sell but it's got a problem which requires fixing.

When on the clean channel, usually after a minute or so of playing the gain channel starts to bleed through in loud bursts and the light on the gain channel flickers on and off.

Any idea what might be going on here? Thanks!
*reported* for wrong forum.

This post would be much better off in Guitar Gear & Accessories.
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Sounds like a dodgey transistor to me. I'm not sure what those use to do the switching, BJT, opto, FET, Whatever it is, that's what I'd be replacing.
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