ESQ-1 Keys not Sounding

[rakk95]

O.K...I have an ESQ-1 that is turning into my "perpetual project"....this question is for the ESQ experts out there.

After working flawlessly for several months since I completely overhauled the unit, I now have a group of 5 keys that don't want to work. Fourth octave on the keyboard, E, F, F#, G, G#.

I know what the issue is NOT - the PCB under the keybed, or any of the diodes or solder joints. I've got continuity on these key contacts. I actually repaired another ESQ with corroded keybed circuit traces, and the pattern isn't present in this case (else there would be another group of five dead keys eight keys up the keyboard). Also, the problem is intermittent. Won't do it at start-up, then problem appears after ten minutes or so.

Ribbon cables and connectors all look good as well.

Was thinking maybe key encoders? I'm not sure how the encoders "read" the inputs from the keyboard. Is a group of five non-sounding notes consistent with a bad encoder?

Have also done a reset several times to no avail.

Thoughts?....

[rakk95]

Bah - I feel like the guy with the "phantom problem" whose car starts running fine at the mechanic's front door.

Problem fixed, but I really can't explain how.