Have a hum in one speaker. What might be causing this? I know this thing is probably junk but have a kid who likes it and I'm trying to fix it up for her.
Is this what you have?
If so it has a piezo electric often known as a ceramic or crystal cartridge. These cartridges are high output, need no RIAA equalization and need to terminate at an input of 1 to 2 megohm impedance.
If the cartridge gas failed then you need the exact model as it has to be the same weight as you can't adjust the tracking force on those old low end turntables.
These replacements are now pricey. A phono preamp will do you no good, as they are all high gain, and 47 Kohm input impedance with RIAA equalization.
The first thing I would do, is disconnect the deck from the amp and see if it still hums. If it does the amp has failed, and unless you have service equipment and no how to go about fault finding and repair this will defeat you.
If the hum stops when you disconnect the deck, then check the turntable wiring. Take an ohm meter on continuity setting and make sure the two grounds are in continuity from cartridge connectors to the amp connectors. Now do the same for the two signal leads.
If all connections are correct, only then think about replacing the cartridge.
I think you have a Astatic, but there are hundreds of models, so you will have to try and match it.
This is one of the very few sources of ceramic cartridges.
Good luck!
There are few of these units left and not much knowledge about them any more as you just found out from the first reply.
