1952 Magnatone M-199-3-J Student Amplifier Troubleshooting (Part 1)

[@flockoglock]

I commented before watching the whole video, sorry, hope the transformer replacement solves the problem. I'm looking forward to part 2.

[@TheGuitologist]

+flockoglock No sweat. The new transformer did NOT fix the issue. Still troubleshooting. It's a weird one.

[@CrowsBrother]

The 4uF + 1K + 20uF formed a pi network,- note the hum first appeared when it was removed. Love your videos ! ;-)

[@sarcophagist4097]

CrowsBrother It also appeared like this in the video that was released yesterday. Unfortunately there is no exact schematic on the 199 to back this up.

[@Bleats_Sinodai]

If the power transformer is still vibrating even after you changed it, there might be a short. If it's not, I'd say maybe a ground loop? Try removing the ground points and wiring them out of the chassis to a common wire. If it fixes the hum, try cleaning/sanding around the place where they connect to the chassis for better contact. If it still hums, I don't know! Take it apart completely, clean/sand down the inside of the chassis, and re-build it with new components? I really don't know what it could be.

[@pauldow1648]

Silverstone and harmony had models similar.

[@flockoglock]

Maybe try a new 6V6? I've seen strange stuff from "good" tubes that have some kind of problem. Thanks for posting these videos, I really enjoy them.

[@TheGuitologist]

+flockoglock I've tried many different 6v6 and 5y3 and 6sl7. I have not filmed all troubleshooting steps, unfortunately.

[@ivanduke]

good luck ! .... put the old transformer back in !

[@TheGuitologist]

+Ivan Duke The old transformer was testing OL on the 6v winding. Still not sure why. What I'll probably do is include the old one and the new lay down bells if/when I sell it.

[@WillyMcCoy50]

The speaker is a Permoflux (395) from California.

[@amphetamineblue4172]

"The stand up sort of bellend" :D