[sdiy] Buffered/unbuffered CMOS in Oberheim logic boards

[Dave Manley]

Unfortunately the answer is probably 'it depends'.  If used strictly for digital functions then using buffered gates is (probably) ok.  If the old timers were doing some oddball analog weirdness only possible with unbuffered gates, then no.  Are there schematics?

-Dave

-------- Original Message --------
 From: g m montalbano <montalbanogm at gmail.com>
 Sent: Sat, Aug 4, 2012 11:00 AM
 To: synth-diy at dropmix.xs4all.nl
 CC: 
 Subject: [sdiy] Buffered/unbuffered CMOS in Oberheim logic boards

>Hello-
>I'm currently trying to repair a severely damaged Oberheim 4-Voice.
>The keyboard module (an overhead board and two channel boards)
>contains several dozen CMOS chips, most of them series A (or U).
>I recall reading years ago someone (Kevin Lightner?  Scott Metzger?)
>posting that it is necessary to use unbuffered parts when replacing
>non-functional chips on these boards.
>
>Is this true?  This period of Oberheim was known for some baroque
>logic circuits (see the memory board for the OB-1 for a good example),
>and I have no idea if there's a way around using these increasingly
>rare (and hellishly expensive) parts.
>
>Thanks.
>
>~GMM
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