Check my post a few days ago about recapping a DMX
I didn't add but the DMX (or was it DX... no matter really)
has a bunch of small sub-boards for the voices. when I was looking at the schematics I noticed that each of the sub boards had several smoothing capacitors for the voltage supply. I don't know about the expander, but I'd bet 10,000 dollars;) its a similar setup.

I've repaired and built a lot of vintage electronic gear and when it's getting noisy or acting buggy I re-cap it. This clears up the problem 90% of the time. It's less risky taking a soldering iron to it then waiting for the capacitors to fail completely and possibly kill those cem chips.

--- In oldberheim@yahoogroups.com , Bakis Sirros <synth_freak_2000@...> wrote:
>
>
>
> ok, swapped both CEM3374 and CEM3372 of voice 5 with another working voice
> chips and still the fault appears on voice 5. so, both the CEM chips are Not the problem...
>
> any other ideas
>  
> Bakis
>
>
> ________________________________
> From: Bakis Sirros <synth_freak_2000@...>
> To: Oberheim group < oberheim@yahoogroups.com >; Oldberheim group < oldberheim@yahoogroups.com >
> Sent: Saturday, January 21, 2012 12:01 PM
> Subject: Xpander problem, any help
>
>
> hi list,
>  
> so, i found a bought a USA model
> Xpander.
>  
> works and sounds great...  ...apart from voice 5,
> which, after its shipping to me, does not pass the auto tune test.
>  
> sometimes the 'PW' ('pulse width', not 'parallel
> worlds'... ok, silly joke...) section of it fails, sometimes the Res section
> fails, sometimes all the section of voice 5 fail (except the vca section of
> voice 5 that never fails).
>  
> clearly seems there is something wrong with voice
> 5.   :D
>  
> even if i activate the problematic voice, after its
> been automaticaly shut off by the Xpander OS, it sounds a bit different from the
> others in filter tone and tuning (of course, as it cannot be tuned,) and very very low in volume.
> another weird thing i noticed: when i direct voice
> 5 in its 'direct' output 5, then, from this output, i can hear all of the
> xpander voices (together with voice 5) but very low in volume.
> all the other direct outputs work as they should,
> for all the other voices.
>  
> i performed software reset, re-sitted all ribbon
> cables and all of the chips in the voice 5 section of the xpander voiceboard
> without success,
> i also performed all the tests for the xpander
> (memory, vmemory, etc...) and all are ok, afaik.
> plus i resitted chip U106 which is responsible for
> the panning output section of voice 5 (after studying the service
> manual).
>  
> is there anything specific i should check
> everything seems connected.... i cannot resit ALL the chips in all boards
> obviously... but maybe i should resit a specific chip from another section of
> the xpander boards.... any ideas / help
>  
> i really do not want to break anything inside the
> Xpander (i do not want to use a soldering iron, after all, everything seems in
> place), but i can remove and easily re-sit a specific chip or two, if needed of
> course....
>  
> btw, after re-sitting the CEM 3374 Dual vco, of
> voice 5, the vco tuning of voice 5 almost always fails... it did not do that
> before.
> but i am very very certain i removed and resitted
> the chip without making any damage to it or its socket.
> (i have replaced chips in other analogue modules
> before without any problems...)
>  
> btw, the seller is very honest and he insisted that
> the machine worked fine (all 6 vooices) before shipping, and i believe
> him...
>  
> thanks in advance for your help!
>  
> best regards,
> Bakis.
>  
> Bakis Sirros
>
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>