Every 8th Key Dead on Ensoniq ESQ-1, any idea what to check on the board?

Synth Repair
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[Ensoniq] [ESQ-1] – [Dead Keys]

Hello! I recently picked up an Ensoniq ESQ-1 (plastic version), however it has 7 dead keys: 12, 20, 28, 36, 44, 52, 60. Every dead key is 8 notes apart which means it is likely a circuit board issue due to the pattern, and cleaning the contacts did not work to any avail. Does anyone have an idea of what chips/connections it would be good to check for this issue?

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Did you get hold of the Ensoniq_ESQ_1_Display_Psu_VcaOutput service manual?

It shows rows/columns for scanning the keyboard.

Check there’s no liquid damage and then continuity test the common line for all the dead keys.

Check the resistor network RP1 to make sure cols 0-6 show 1k to gnd.