----- Original Message -----From: Frank SimonSent: Friday, July 16, 2010 10:05 PMSubject: Re: [SequentialCircuits] Prophet 10 reworkThe sample and hold circuit has some poly np capacitors plus a few down by the VCA. The schematic only says Poly. Are these Polyester film, Polyester metallized, or Polypropylene film or does it matter which. Everything I see at RS Component is Radial not Axial like the original. I know that doesn't matter but I was wondering about these different technologies.----- Original Message -----From: Frank SimonSent: Saturday, July 10, 2010 3:10 AMSubject: [SequentialCircuits] Prophet 10 reworkDoes anyone have a strong opinion on replacing old parts on Prophet 5 or 10 like capacitors and 4000 series and 74LS series ICs. I definately am replacing tantalum but are the highly populated .1uF Z5U caps Mica or ceramic and do they really go bad? I understand mica is obsolete in terms of current production so I am thinking to replace mica with ceramic if this across the board rework happens. I have declared war on my P10 and plan to replace all parts on the PCB3 board (computer board) like caps and logic ICs. There is a guy with a nice website that states the logic IC technology was poor in the 70s with a 6 micron fabrication process versus a current 0.7 micron process that the reliability of the old chips were poor. I figure this is the way to go first before I question the DAC71, which costs a fortune. The way I look at it is it is a rework that probably is healthy for longevity. I am not sure how to troubleshoot the DAC.
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Message
Re: [SequentialCircuits] Prophet 10 rework
2010-07-18 by Frank Simon
It appears at one time there was a poly film 150pF
by Evox, which is my Prophet 10. I cannot find a poly film 150pF. All I see
is ceramic and Mica. Has anyone experienced this?