So, I'm checking the bias of my JCM 800 (getting it ready for a friend to buy), and notice that I don't get any sound out of the unit when it's upside-down. :laugh2: Yes, the speaker connection is solid! Without changing a thing, I get sound by turning the amp right-side up. What's going on??? Is some loose connection shorting out? To add to the mystery, when I probe pin 8 on a power tube socket, it seems as if I don't get a reading for the plate voltage. I've probed it before and it should be ~480v.
My Amp doesn't work upside-down???
- Thread starter mrid
- Start date
Gearjoneser
Gear Ho
Re: My Amp doesn't work upside-down???
Don't tell your friend. He'll probably never turn it on, upsidedown. I dunno. I can only think it's a power, input, or speaker connection that gets broken from gravity pulling a wire the opposite direction. I had a problem with an old Marshall shorting out intermittently. It turned out to be bare wire too close to the chassis, and the wire kept arcing current against the chassis.
Don't tell your friend. He'll probably never turn it on, upsidedown. I dunno. I can only think it's a power, input, or speaker connection that gets broken from gravity pulling a wire the opposite direction. I had a problem with an old Marshall shorting out intermittently. It turned out to be bare wire too close to the chassis, and the wire kept arcing current against the chassis.
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