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Selmer Pianotron (Weltmeister Claviset) looking for schematic!

Started by iamdamosuzuki, January 21, 2023, 10:09:24 AM

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hi all,
i have a selmer pianotron i'd like to get up and running but no one i've encountered will take a look without a service manual or schematic. i'm based in the US and figure the transformer is 240V so have not attempted to power it (the preamp board was desoldered and the power supply section looks like it's also been desoldered) the person who gave it to me bought it on ebay a decade ago and couldn't remember much about it's origins or what he personally may have done to it (probably the desoldering - i don't think it's missing any parts). i figured this is the best place to ask - does anyone have the service manual/schematic? i'm eager to make some tunes with it!  :o You cannot view this attachment.

here's a google drive to give an idea of what it looks like inside:

thanks! 8)


I was under the impression that Clavisets ran off of a 9V battery. Perhaps this one was modded to run off something like a one-spot? Is there any kind of power jack or cord on the underside of the instrument?

Where do the red and black wires on the right side of the PCB run to? Those are likely your voltage and ground to the PCB. If they are not connected to anything, you could clip a 9V battery to them to power the board. You'll have to check the polarity of the circuit though - those old germanium transistors are likely PNP, which means a positive ground, i.e. the positive side of the battery would go ground (black) and the negative side goes to the power (red). If the positive (banded) ends of the electrolytic capacitors on the PCB are all going to ground (check this with a multimeter), then the circuit is most likely a positive ground.

No schematics here, but some pictures that do show a battery terminal in place of the transformer in yours: