SCI Pro-One problem

[Arthur Harrison]

Perhaps a power supply is going awry after warm-up?

Monitor the supplies with a 'scope, if you have one, 
or at least a voltmeter.  I've got one of these synths, too, 
BTW!

-Art


-----Original Message-----
From: Hess Hodge <Hess.Hodge at Colorado.EDU>
To: Synth-DIY <synth-diy at mailhost.bpa.nl>
Date: Wednesday, December 09, 1998 4:34 PM
Subject: SCI Pro-One problem


>Sorry for the cross-post.  I posted this to Analogue Heaven and did not
>receive any responses.  I am hoping that someone here can help me in
>diagnosing this problem... thanks,
>Hess
>
>-/\= Hess M. Hodge
>~/\  hess.hodge at colorado.edu
>(/\) http://rtt.colorado.edu/~hodge
>
>
>---------- Forwarded message ----------
>Date: Tue, 8 Dec 1998 23:17:56 -0700 (MST)
>From: Hess Hodge <hodge at rintintin.Colorado.EDU>
>To: analogue <analogue at hyperreal.org>
>Subject: SCI Pro-One problem
>
>Hello,
>I just received a pro-one (my very first analogue synth!) and I am
>having some problems.  I found some references to the same symptoms
>in the archives, but no insight into the problem itself.  Here is what is
>happening (you must excuse my limited synth vocabulary):  After only
>playing a few notes the synth will stop working.  The keyboard stops
>responding and the unit either makes no sound, or the gate LED lights up
>and the unit glides up to the highest note and stays there.  No further
>tweaking of any keys switches or pots can get the unit back or produce
>any different output. Only a power cycle will reset the unit and make
>everything work again (temporarily).  This problem will occur on its own
>(ie, I'm not doing anything but pressing keys) or when I try to use the
>sequencer or the arpeggiator.  When using the sequencer or the 
>arpeggiator, the synth will usually play a bunch of random notes before it
>dies.  I opened it up, checked all the connections and made a visual check
>of the PCB, but I couldn't find anything unusual (except for the shrooms
>;)  Has anybody seen these symptoms before?  Know what the problem is?
>How to fix?  By the way, it is ser # 100-5557 with a J-wire keyboard.  Any
>help is very much appreciated!
>hess
>
>-/\= Hess M. Hodge
>~/\  hess.hodge at colorado.edu
>(/\) http://rtt.colorado.edu/~hodge
>
>
>