Playmaster Series 200 Circuit

[Tel]

Hiya folks,
I've just picked up an old Playmaster 200 I'd like to refurbish. One channel works fine, the other sounds dead - but there was some warmup "rustle" on the other when turning the bass control, so I think both output channels are good. I haven't started troubleshooting yet, I had hoped it was the balance pot but that checks out OK, although a bit odd - it seems to be 2 linear 10k pots where the range works zeroR to centre then rising to 10k for last 1/2 turn - mirror image each side - presumably to keep crosstalk down. Don't fancy finding a replacement for that, will probably go with Left and Right volumes if it's an issue. BUT! Does anyone have a copy of the circuit diagram, or even the construction articles? I though it must be on the net somewhere, but a couple nights on google haven't found anything... cheers,
Terry

[wintermute]

hehe, Mines dead on one channel on the preamp as well. I have a bypass of the preamp and I'm running it off the HTPC direct. I thought that if I didn't fix the preamp that it would give me motivation to work on my new one. Unfortunately not

I have the schematic somewhere, but I have moved house recently so finding it might be an issue.

I've actually modified mine. I bypassed the tone and balance controls completely, and also made some modifications to the last opamp stage (I think after the volume control) based on the revision to the design of the Playmaster 60/60. This improved stability as the preamp section was prone to oscillation.

I like the amp. Definitely worth fixing I'd say. Even if you just bypass the preamp and use it as a power amp

here is a thumbnail (the gallery is dead at the moment) of mine the first time one channel died. My 2yo poked a chopstick in through one of the holes where balance or tone pots used to be and broke a component leg off


Tony.

[Tel]

Hmmm - thanks for the suggestion - that's not a bad idea at all. I think I'll pop in a set of pre-out/in sockets, that way I can feed it straight from the PC in my study while I think of my next move. I was hoping to move it to the workshop next door and run some big old Sansui's off it, but that can wait - I have a Sansui AU-D9 that has a dead output side that I'd like to fix for the study, then I can either sort the preamp in the Playmaster or just run it off the tape outputs of the Sansui... hmmm, way too many broken toys, way too little time

[wintermute]

Just one thing to be wary of. The output of the preamp section has quite a dc offset on it. If you switch from direct to internal preamp you may get thumps. Best to switch the speakers off with the speaker switch before changing between direct input and preamp input.

Tony.