[sdiy] arp ody problems part 2

[gregory zifcak]

when i got my odyssey vco2 square wasn't working, it turned out to be a 
scraped off circuit trace. don't know if this is helpful at all; doesn't 
seem like it would be a common problem.


>From: Tim Parkhurst <tparkhurst at siliconbandwidth.com>
>To: "'Tim J'" <bob_aloha at hotmail.com>, synth-diy at dropmix.xs4all.nl
>Subject: RE: [sdiy] arp ody problems part 2
>Date: Tue, 8 Jun 2004 17:44:26 -0700
>
>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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