[sdiy] arp ody problems part 2

[Tim Parkhurst]

Hi Other Tim (about the fourth or fifth one, I think),

My first guess would be the switch in the VCF mixer that selects between the
saw and square waves. A flakey switch could give you the problem you're
seeing. After that, maybe the mix slider, although this should affect both
waves the same. It's also possible that the output circuitry on the VCO is
bad, although I think this would give you other symptoms. I really think
that if the VCO is behaving okay, then the low output levels are being
caused by something else. You're going to make troubleshooting the Ody MUCH
easier if you have the schematics and an oscilloscope, even a cheap one. If
you already have these, then start at the output of the VCO and see where
the square wave signal dies off. 

Hope this helps!


Tim (ARP gear slut) Servo
"Imagination is more important than knowledge." - Albert Einstein



> -----Original Message-----
> From: Tim J [mailto:bob_aloha at hotmail.com]
> Sent: Tuesday, June 08, 2004 4:19 PM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] arp ody problems part 2
> 
> Hi guys.
> 
> I mailed the list a week or two ago with powersupply problems on an old
> odyssey.  Steve, Roy, and Dana thank you all for your suggestions.  The
arp
> is back up and running.  Still having a couple of problems.  VCO 1
controls
> for course/fine dont seem to be responding (as well as the modulations).
> Also, there is no square wave output. The output is also very faint.  (so
> there is just a very soft saw drone)  Anyone want to venture a guess or
> suggest a place to start tinkering?
> 
> Thanks,
> Tim
> 
> 
> 
> >From: Steve Jones <agenttriez at mac.com>
> >To: Tim J <bob_aloha at hotmail.com>
> >Subject: Re: [sdiy] arp ody Power supply or +/- 15v PS
> >Date: Wed, 02 Jun 2004 14:27:33 -0700
> >
> >Almost certainly you have shorted or leaky tantalum capacitors on the
power
> >supply board, or, more likely, on one of the main boards where the power
> >supply connector plugs onto each of the 3 boards there are 2 tantalum
> >filter caps next to the connector. This is epidemic with ARPs' and all
> >tantalums in the machine should be replaced.
> >
> >regards Steve.
> >
> >On Wednesday, June 02, 2004, at 01:16PM, Tim J <bob_aloha at hotmail.com>
> >wrote:
> >
> > >HI all,
> > >
> > >I'm not much of a tech but...my arp ody power supply is only putting
out
> >+/-
> > >5v.  I've checked all the resistors and they are ok.  Anyone have an
idea
> > >what causes a drop like this?
> > >
> > >Also, I was thinking of just a new powersupply for the little beast.
> >Anyone
> > >know of any cheap powersupplies that would work?  It doesn't have to be
> > >internal as I dont mind wiring it up.
> > >Anyone know about how many amps the odyssey needs?
> > >
> > >
> > >Thanks,
> > >Tim
> > >
> > >_________________________________________________________________
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> > >
> > >
> 
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