Vintage Synth Repair

Wow, that's a lot of questions. I can help out, but
not all at once, I have  a workshop full of synths at
the moment that I am fixing 1 by 1. Starting the the
Prophet 10, do you have a service manual for it?


--- Frank Simon <fsimon001@...> wrote:

> Hi Steve,
> I hope everyone doesn't attack you at once. I had  a
> crazy experience where I bought a Prophet 10, Korg
> Trident Mk II, and Roland JX 10 all for $30 each non
> working. I am an RF engineer and novice
> musician/Audio repairman. I know linear more than
> digital but I am going to throw out some questions
> since you offered. 
> 1)My Trident I fixed due to NiCad battery meltdown
> destroying traces but I repaired the PC board(with
> wire) and all works great Strings, Brass,
> FLANGER!!!, but the Synth section makes occasional
> odd noises sounds like processing. Any trouble
> shooting advice would be appreciated.
> 2) The P10 had no sound, lit up, I found a 5V
> regulator pulled down. Found the bad IC(burned my
> finger). Then like a dumb a## I was checking -5V reg
> T0-220 on a voice board,slipped shorted output to
> input and took out 4 CEM3310. OUCH!! Still don't
> know why due to internal Zener in CEM3310. I want to
> continue toubleshooting but don't want to buy pricey
> chips until my confidence is up. Can I put the board
> in without 4 of the 10 CEM3310 and continue. I'm
> sure no sound but -5v reg will be up. Any advice
> appreciated.
> 3) Roland JX10 is total dead. I think power supply
> was good. Lower priority. This one I don't have a
> schematic. Do you have one?
> 4) Finally my Hammond H-112 had low volume and I
> found unplugging the Reverb tank it came back full
> volume. I think the reverb is ok. Do you think it
> could be a tube driver? Sounds odd that it would
> shut the amps down.
> 
> Sorry for the overload. I'm excited about these
> synths. If I fix one I got more than my money back.
> The Korg is very close. I will cry if I can't fix
> the P10.
> Thanks,
> Frank
>  
> 
>   ----- Original Message ----- 
>   From: thirteentech 
>   To: vintagesynthrepair@yahoogroups.com 
>   Sent: Tuesday, April 15, 2008 7:54 AM
>   Subject: [vintagesynthrepair] Hi from a new
> member.
> 
> 
>   Just wanted to introduce myself... I am a
> synthesizer service tech from Sydney, Australia. I 
>   have been fixing synths since 1982, as well as a
> lot of touring as a keyboard tech. Currently I 
>   have around 22 vintage machines that I play and
> use for recording, and have been a warranty 
>   tech in Australia over the years for PPG, Kurzweil
> E-mu and Sequential. Hope I can help out a 
>   little on the forum, and learn some new things too
> :-)
> 
>   Steve Jones.
> 
> 
> 
>    



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