----- Original Message -----From: Stephen JonesSent: Tuesday, April 15, 2008 9:35 PMSubject: Re: [vintagesynthrepair] Hi from a new member.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@neo.rr.com> 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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Message
Re: [vintagesynthrepair] Hi from a new member.
2008-04-18 by Frank Simon
Hi Steve,
I have a manual I downloaded from
paintingwithsound.com. It is hard to read. I was a little disappointed when the
power supply in my schematic states VR603 was 12v T0-3 down to the wire color.
Later to find out as I traced it to the PCB9 Polyphonic sequencer CPU board it
needed to be a 5V. It took out a Dual Flip Flop U931. After that I put a proper
5V in and nothing is shorted. But doesn't mean something else was't damaged on
that board just not shorted. That same part was originally bad when the original
5V Reg was in then the 12V took it out again. That was the first bonehead move.
And as you may read from my first mail the CEM3310 story. So my progress is
negative. If you can offer a systematic approach to trouble shoot this maybe by
isolating boards or whatever I would appreciate it. If you have a readable
schematic you can share it would be great.