On the three boards under the keys, everything appears to be fine (no burned out diodes, no scoring or scratching) but a stretch of a handful of keys that are over the middle board produce no sound. The cabling appears intact. Swapping out keys and rubber contacts with known good ones from other locations on the instrument has no effect. I’m wondering where to start troubleshooting. If it helps I can get some pictures with the non-functional area later today.
Anyone have any ideas of anything I should be looking for? The area that doesn’t work is contiguous, but it isn’t all of the keys on the middle board, just a subset of them.