Vintage PAIA "Drummer boy" drum machine.....Help!!!

[zynvaadi]

Thank you all in advance for my newbiness. So i am very new to electronics fiddlin, very new. I am however an electrician by trade so i have potential i think. I am a recording engineer and musician to give you a little bit about myself.
Anyway i got this old drum machine, very old and rare apparently. When i turn it on and plug it in, i get this crazy loud screeching sound. Real loud. I plugged it into a guitar amp and have it down as low as it will go. I opened the unit up and found these "components" that you can adjust with a screwdriver. I think each drum hit section has it's own one. Volume control maybe? Anyway when i turn them they make some pretty cool strange noises. And if i turn some of them down the noises go away. But nothing on the drum machine works. No beats. Not even distorted messed up beats.
Do any of you kind people have any idea what this noise is? And is it hard to repair or expensive to have a tech fix it? It's probably from the 60's early 70's. The circuitry doesn't look very complex.
THANK YOU!!!

[52 Bill]

Welcome to the place. I'm not sure, but some of the PAIA drum machines used a twin t oscillator circuit to create the different drum sounds. The circuits were tuned to a point where they almost went into oscillation. It may be that some of your cicuits need to be readjusted to not oscillate.

Go over to the PAIA site and see if the schematic and user manual is available for download and see what you find out.

[zynvaadi]

Thanks a lot Bill, i'll try that. It is so old and i have never heard of that company, i did not think they still exist.

[zynvaadi]

Thanks a lot my man. Downloaded schematic with some repair test info.

[Mark Hammer]

Any old-school electronic drum unit will have a noise generator on board, for producing snare drum and/or cymbal sounds. While the tone generators used to produce bass, tomtom, or other wood tones are usually damped oscillators that will "ring" for a little bit then die out, the noise generator stays on all the time, and something has to bring it in and out of the mix.

The "snare" part of the Drummer Boy is the part formed by Q29-32, with Q31 being the noise generator Identified by being the only transistor with one connection left open). My guess is that, unless you described it in a way that is misdirecting me, somehow the noise is staying on all the time when it shouldn't.

(I have been helping in the gradual sale of the estate of a late friend of mine who collected a lot of synth and guitar-related electronics. One of the many e-drum units sitting in his basement, on top of several Zoom and Yamaha units, and a Mattel Synsonics, is a PAiA Drummer Boy. I have not booted it up to hear what it does, but I see there are Youtube videos for it that might tell you what it is supposed to sound like. http://www.youtube.com/watch?v=9-Vi8q16GTg)