Synthfilter: Sequential Circuits Prophet 600, keys not firing issue

August 31, 2009 9:36 AM

Synthfilter: Sequential Circuits Prophet 600 giving me problems: keys not playing notes, but silicone contacts are clean and working. Looking to be directed to the right person/place/forum to ask or maybe someone here can help

I have recently become the owner of a Sequential Circuits Prophet 600 which has been in a box since 1987. It is having an issue with the key mechanisms properly hitting the keyboard contact strips. When I powered it on, only three of the highest far right keys worked so I opened it up and cleaned the contact strips then plugged the keyboard circuit board back into the synth without reattaching the actual keys in order to test it. The rubber keyboard contacts fire notes just fine when depressed with a finger but for some reason when attached to the actual keyboard mechanism, most but not all are failing to fire. The top couple and the bottom three play and a few in between but that's it. The plastic keys don't seem to be warped or anything, it just looks like when they push the plungers down that they aren't descending far enough down in order to complete the circuit. I suspect this has something to do with it because I am able to make more of the keys play if I push down on the end of keys nearest circuit board, in other words the end of the key opposite to where you would normally hit it. I'm thinking maybe I can attach little pieces of cardboard to the bottom of the keys where they touch they silicone contacts so that they push down a little more, but I don't want to screw this instrument up...Anyone seen this issue before or know a better place/person/forum to ask? Any ideas?

posted by Charlie Lesoine to technology (3 comments total)

You'll probably get a better response asking on the Analogue Heaven mailing list; that's the most likely place to find collectors and restorers of that kind of synth.

(Lots of links on that page are dead, but don't worry, the list still works!)
posted by xil at 9:45 AM on August 31

You can get replacement key contact strips at http://www.winecountrysequential.com/ as well as a bunch of other spare parts and service manuals. (The p600 page is at http://www.winecountrysequential.com/page5.html .)

I don't have a p600 or fixed this problem in the past (sorry!) but I've bought spares from Wine Country in the past when repairing Sequential gear so they may even be able to suggest the best way to repair it.
posted by rubadub at 10:29 AM on August 31

I already emailed wine country and am waiting on a response from them. Considering just buying new strips but I'm afraid that wont fix the problem...
posted by Charlie Lesoine at 10:51 AM on August 31