Sequential circuits samplers

you know more than me i guess, i really enjoy my p2000
i had small trouble when i switched potometers , it just read the readings
wrongs , ever tried just un hooking the disk drive and see what happens?
 i can imaginne intermitting loose signals from boot up time causing some
interferance but guess work may not be enough for your situation

mine did do similar but i cleaned contacts on the potometers , that dust is
crazy and believ it or not transfers enough "juice"
to carry curent to the switching of parameters,,, loose ground wire on alot
of pcb board should be checke too!!!

charles    and mount disk drive on rubber!!!!
----- Original Message -----
From: "TonyB" <tbarros@...>
To: <prophet2000@yahoogroups.com>
Sent: Friday, May 23, 2008 5:10 PM
Subject: [prophet2000] P2000 refurbishment -- was Re: What's special


> Hi charles, thanx for your interest.  My P2000 EPROM is Rev3point0.
> Without any diskette, the P2000 should "boot" with 12 presets as
> selected by the 12 membrane buttons on the front panel.  The <PRESET>
> LED should be lit after boot.  All keys should be live.  Put Mix knob
> in center. With a diskette inserted at powerup, <PRESET> LEDS 1-4
> should sequence as the patchs are loading.  Turning <PRESET> off will
> allow editing of the individual presets. The internal presets are
> called the following: 1. Solo Synth  2. Bells  3. Bright 4. Organ 5.
> Woods Section 6. Wah Synth 7. Pad 8. Expressive Synth 9. Plug Bass 10.
> Electric Piano 11. Brassy 12. Synth Bells.  The organ sound is
> excellent, BTW. If pressing a <PRESET> button causes other LEDs to
> lite, there is a problem in the switch/LED/pot multiplexer.  The CPU
> is working fine. There IS audio out for all keys in any <PRESET> that
> is stable. That means the Curtis VCFs and VCAs are working. I'm making
> a list of ICs to be replaced.  afn  T
>
>
> --- In prophet2000@yahoogroups.com, "charles midi gfa pascal"
> <charles.copp@...> wrote:
> >
> > i think if you have an upgrade to version 3 or 4 of the system rom
> installed
> > all keys work and it remebers the presets , if not v 3 and under all
> keys
> > don't work and needs disk to work  or hear any sound...
> >
> > charles
> > ----- Original Message -----
> > From: "TonyB" <tbarros@...>
> > To: <prophet2000@yahoogroups.com>
> > Sent: Friday, May 23, 2008 8:27 AM
> > Subject: [prophet2000] P2000 refurbishment -- was Re: What's special
> >
> >
> > > OK P2000 fans, here is a quick update of my repairs so far.  First, I
> > > dissassembled the entire unit(all pcbs removed).  I cleaned all the
> > > insides of the P2000 including the inside of the case and the tops and
> > > bottoms of all pcbs.  My P2000 has a 512K memory pcb. After
> > > resoldering some connections around the keyboard multiplexer IC, (the
> > > large 40pin near the left edge; it's labeled "keyboard"), I now have
> > > every key working now!!  But, unfortunately, the 12 patches are not
> > > working corectly.  Before, the keys were intermittant, but the 12
> > > patch buttons/LEDs worked OK.  Now, all the keys work OK, but the
> > > patch buttons/LEDs jump around when pressed or when some keys are
> > > pressed. There is still a multiplexer problem.  My instincts say it's
> > > on the front panel multiplexer pcb. I will order some new ICs soon.
> > > Another note:  the filter was not "working" before; now, I can get
> > > the frequency and resonance changes on certain patches.  This, again,
> > > points to multiplexer problems.  More when I get time...   T
> > >
> > > --- In prophet2000@yahoogroups.com, "TonyB" <tbarros@> wrote:
> > > >
> > > > Ok P2000 fans, I got my P2000 opened.  Surprisingly easy to service
> > > > with the built-in hinge in the back!!  OK, I have a Q for any of you
> > > > that have a fully functional P2000:  With no diskette, after booting
> > > > up, are all keys working??  That is, i select built-in sample #4,
> > > > which is a great, IMHO, hammond sample, does every key play a note?
> > > > What about the L/R knob??  For sample #4, is the sound ONLY on the
> > > > Left? PLMK, so I can continue troubleshooting my P2000.  thanx. T
> > > >
>
>
>
>
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