JVC-Delmonico AM/FM stereo tube radio

[Jeffhs]

Originally Posted by radiotvnut

Here's a circa '63 JVC-Delmonico AM/FM stereo Japanese tube radio, model FMS-413U, that I bought for $10 at the flea market. The lady said she plugged it in and she heard a loud POP, followed by a wisp of smoke. Once I removed the back, it didn't take long to see what blew up - the capacitor that's wired across the AC line. This is yet another example why people shouldn't plug in a tube radio without first having it checked/gone over by an electronics technician.

As you can see, this is an AC/DC radio and looks to have a 35C5 output tube for each channel. It will be interesting to see how this performs when it's restored.

See Johnny (The Raster Master)'s post in the TV forums for an excellent example of what can and all too often does happen when a radio or TV is indiscriminately plugged into the AC line, without first replacing old filter caps.

Does the radio operate normally with the line bypass capacitor out of the circuit? I would think the reason the capacitor exploded in the first place was that it was shorted; of course, when these capacitors short, they put a direct short circuit across the AC line and will smoke, pop and explode just as you described. However, I am surprised the line fuse (if present) or the shop's circuit breakers didn't open as soon as the radio was plugged in.