Is one very fascinating piece of electronics. Problem is that the service docs I have are for serial # 961450 and later that apparently look like this:
I have, in for service, SN 870926. The appearance is different and the pcb’s have no resemblance to the docs. The model # is the same and the basic function is the same, but every board I have looked at does not match layout, pinout or IC application as shown in the available documentation. I fixed this same unit about 12 years ago for the same customer and I must have lucked out and stumbled into a latched up op amp as the repair was quick and cheap. No such luck this time. I could REALLY use some applicable documentation but there does not seem to be any. I have located a couple of places on the net that have JPG files of the same docs that I have - dated Oct 1980, but nothing else.
Anybody out there know anything about this?
I have the service notes dated Sept 21st, 1979
But they’re actual legal length paper.
Wanna buy 'em? 
Thanks so very much to theglyph who sent me this link.
http://egrefin.free.fr/eng/studio/vp330E.php
Man! I searched to the best of my ability and could not find this on my own. Maybe you wanna add those pdf files to your collection Kevin. We know how to find you!
Thanks also to this forum and all of you reading and posting to it. What a great resource.
Thanks.
I’m short on bandwidth right now, so won’t download that copy, but I assume it’s the same one I have.
I don’t think there was an earlier one, but never knew Roland redesigned it later either.
Any ideas why? Different BBD chips? Key action?
So far the only obvious observation is that there was a face lift. The original has old style Roland appearance with rocker switches and the new one has shadow style switches with LED indicators and a more modern look. I have not looked close enough to identify much else other than the pcb’s have different layouts with different connector counts.
With the correct docs, this job turned out to be really fun. Page 8 of the docs @ link above has the entire schematic on one page - really nice if you are zooming in and out with Acrobat. The vocoder board is very similar to the new one and much of the circuit and layout applies to both. The main difference I noticed on that board is the T-220 series pass regulator Q’s for +,- 6.8 V are gone from the upper right corner of the board and the trim pot layout is adjusted. Knowing this, and having a copy of the wrong layout, of such poor quality it is practically useless anyway, i was stumbling around this circuit “in the dark”.
The result of the failure was that the input compressor was stuck at full gain, and the output expander was shut down. It was fun sniffing that out with a scope probe.
The problem turned out to be a bad IC ! in the compander level detector. I checked for latched up op amps here, but this one just had a dead pin 1 - stuck at ground. Easy to find when you know what you are looking for.