Privia px-s3000 repeating dead key pattern

[Sprint 75]

 I recently purchased a used Privia with about 20 dead keys. I was thinking it was a cleaning issue as the owners cat was slepping on it ....🙄

After a teardown and carefull cleaning that made no improvement  I noticed the dead keays were in a repeating pattern 6 keys working then 2 keys  dead across the entire keybed.  I'm thinking this pattern should  be a clue to the cause. (maybe the ribbon connector?) In the meantime I'd like to use it a sound module controlling it with another keyboard but I'm not sure how to do that since it doesn't have conventional MIDI in /out connections.

Any help with either issue would be appreciated.