by Rob-NYC »
Tue Feb 12, 2013 9:49 am
The fact that one channel is dead/low is not surprising, this was the same problem (among others) with mine. I have the ability to rebuild and test electronic assemblies so it was just part of the fun. You can check the speaker connections and use the low voltage AC range of your meter to look for signal at the speakers. But it is likely an electronic problem.
The principal problem in mine was old capacitors in the tone amp section, but given it's age, it is likely that full performance will require replacing all or most of the capacitors. This isn't a big deal IF you know how to solder, read the voltage and capacitance ratings on each capacitor and observe basic procedures.
From your pic (i see only one) it looks similar to mine. I have the Sams Photofact schematics and chassis pics for this era. they are for Chassis R204-08-00 thru R204-17-00. If that is your range, these may be helpful. If not, you can still just replace the small electrolytic capacitors, they are common values, or consider having a local tech do it.
As for the wiring of the AUX vs phono inputs, this is normal in these sets. Magnavox used a low output ceramic pickup cart. The reason is that tracking ability increases as the needle cantilever is allowed to be more flexible. This however means that it is making the grooves do less work in generating electricity -so lower output. Typically that cart was lower than the normal output of a tape deck and the internal radio. So to make the sources balance, more gain is allotted to the phono input. There are simple changes that can give extra level (gain) to the AUX input but you run the risk of distortion on loud records. See if the what you added to the AUX roughly balances the radio in level. If so, leave it as-is.
My reference to a light bulb in series with the power cord is for it to act as a sort of cushion or current limiter. As I said, if you jump the wrong two wires coming from the receiver to the phono it will place a dead short across the power line. Putting a bulb inseries with -one wire- of the plug will prevent any chance of damaging the set's switches or wiring. If things are wired incorrectly, the bulb will light fully. Correctly wired it will be dim if at all.
Do a google image search for "light bulb current limiter" -very simple circuit.
Rob/NYC
"If we believe absurdities, we shall commit atrocities" -- Voltaire