Hi Ed,
Tuner cleaner is good for pots but not switches, sliders, or key contacts. For sliders, it removes the lube and makes them stiff. Now I know that may sound paradoxical because tuner cleaner HAS lube in it - it's just not the right kind I guess. Use only compressed air to clean sliders. For switches, tuner cleaner just gunks them up. I recently found this out when doing the contact switches on my EX800. I eventually got them working again after multiple applications of contact cleaner. Thank god I never tried tuner cleaner on my
key contacts! The more I use tuner cleaner, the more I hate it and realize it has ONE use - cleaning pots. It's next to impossible to dispense a *small* application of the stuff. One little spritz and it's friggin' everywhere! There is a product called Cramolin Red(do a google search) that is supposed to be "everything that tuner cleaner isn't". If you've got tuner cleaner all over your contact area, you should clean it(and the rubber strip) off with 99% isopropyl and q-tips before trying the eraser solution below. The lube will
prevent the eraser from working.
I just finished fixing intermittent keys on my DX100. Here's what I posted on the YamahaDX group:
I used an eraser on the circuit board contacts, then cleaned off the eraser
residue with 99% isopropyl. Having done the problem area, I realized that the
rest of the keys were now not triggering as quickly as the freshly cleaned
area, so I did the whole keyboard. Like new now! I should say that the film
of oxidation was virtually invisible and I didn't notice it until I had
cleaned an area and compared it with the uncleaned portion. Here's where I
found out about the eraser. It's a vintage synth site but has lots of
universally applicable repair and maintenance tips with great pics.
http://www.oldcrows.net/~oldcrow/synth/korg/polysix/keyclean2.html
Hope this helps,
Shayne