[sdiy] prophet 600 -- tough problem

[IXQY at aol.com]

 Hi,
 If I may ask...what are the symptoms with your Prophet 600? Will it play at 
all?  I have problems with mine sometimes when using lots of pitch bend, mod 
wheel or playing fast solos. Sometimes notes will get lost and sometimes 
notes will "hang". I've noticed latency with the note-ons too. 

 I just got through doing a recording using the P600 and had to restrict use 
of the performance controllers because of these problems. The setup I was 
using was P600 MIDI out ->Encore Expressionist -> MOTM modular, but I've 
noticed it while playing just the P600 alone. I have the latest OS installed 
(6.08).

 Has anyone else run into this problem with their Prophet 600s?

 Thanks,
  Andrew


> From: "greg montalbano" <greg.montalbano at ucop.edu>
>  To: <synth-diy at dropmix.xs4all.nl>
>  Sent: Tuesday, June 04, 2002 3:46 PM
>  Subject: [sdiy] prophet 600 -- tough problem
>  
>  
>  > Hi--
>  > I'm hoping to hear from anyone who has specific, detailed knowledge of 
the
>  > workings of the digital portion of this synth.
>  > I have several control voltages that are completely screwed;  but the
>  > problem is definitely upstream from the four 4051 demultiplexers*.
>  Looking
>  > at the outputs of those four ICs in order (on schematic "Board 4, page 1
>  of
>  > 4"), the bad CVs form a pattern: 00X00XOO XOOXOOXO etc etc, where O= a
>  good
>  > CV and X= a bad one.  This leads me to suspect a problem with the data or
>  > address lines controlling the DAC and/or demultiplexers;  can anyone tell
>  > me exactly what to look for and where to look?
>  > Everything else on the synth is functioning correctly & consistently.
>  >
>  > Thanks.
>  >
>  > ~GMM