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I believe (90%) that KR-500, D70 and Rhodes 760 are having the same coil strips. These 3 keyboards are all with 76 keys and as I see your photos these are matching with my Roland's D70.
We can be sure if you have the codes.
My D70's coil strips codes are:
SK-776-AW:
a) Contact Board 32P ASSY 762162300A
b) Contact Board 44P ASSY 762162400A
also check here: www.dropbox.com/sh/cslt2uo1l7sf4dj/SEn5gAlrJW
and for any other info, just mail me!

I know it's been a few years, but maybe someone else with the same problem (like me!) will find an answer here: I'm using sodium hydroxide solution (lye, in the form of crystal Drano drain cleaner) to remove the glue. I mixed about 1 teaspoon in 2 cups (500 ml) of water, and leave the keys to soak for hours. A cotton swab removes most of the residue, but you might need a dental pick to get into the corners. Sodium hydroxide is hazardous, so be sure to wear rubber gloves and eye protection, and plan ahead of time where you're going to put the gloves when you take a break! After soaking and wiping away the glue, rinse in fresh water, dry, and re-glue.

Well the answer is called "Sodium hydroxide", known as Caustic Soda which actually is NaOH:
http://www.soundonsound.com/forum/showflat.php?Number=623176
I've managed to do a full restoration of all the keys of my D70 (same as KR-500, JD-800, U-20, KR-55, SK-7X, Rhodes 660 or 760 -models made by Roland).
I have also managed to repair the rubber contacts, using a fine sandpaper (at least p2000 or higher), and rubbing/scrubbing very gently and carefully the black contact edges on the underside of the rubbers who make the 'touch' on the green contact board.
Be careful just to scrub all surface the same amount, and NOT use the sandpaper in angled position.

Hi Thanks for this post i saved an old kr-500 reproducing the repair method here .

Clean all the plastics keys and springs
Clean many rubber carbon pad with alcool
Redraw the pcb strip with silver paint from amazon/alyexpress.
Use a peace of styrofoam place above the strip compressed by metal corner of piano to make good contact ( dont work without )

6 hours laters works again remainnings issue : dead pot for tempo one push key dead not really motivate to reopen for this because all time you open it you "force" on the pcb strip from the right