Anyone have information on the GEM PK4900

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Anyone have information on the GEM PK4900

Post by synth3tik » Tue Feb 08, 2011 8:14 am

Hey all,
I just plucked a rare GEM PK4900 off ebay. Sadly when I fired her up I found her to be DOA. This piece is so rare it seems impossible to find any information on it. I don't even really know whats wrong with it. It is totally possible that it may just need a good cleaning, or a quick re-solder, I don't know at this point.

The unit powers up, but does not produce any sound. One start up I was able to get a gush of white noise. Underneath which I could faintly hear the "Instastings" section, and I was able to manipulate the pitch with the keyboard. So from that short 20 seconds I am able to ascertain that the keyboard and output stages work. Which kind of sucks because these would have been possible easier fixes.

Anyone with information or first hand experience with a PK4900 would be awesome. This synth has quite a bit of pitiful charm.

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Re: Anyone have information on the GEM PK4900

Post by sam » Tue Feb 08, 2011 8:54 am

Having fixed GEM organs from the same era i can give some pointers, I presume you know what your doing with a multimeter because i suggest first you check the power supply.

Check the tantalum caps for short circuit....

Unplug the gem before you dive in...
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