Electro 3 Missing sound on 6 keys

[bigfootstudios]

I recently received an Electro 3 73 that had experienced some fall damage. It has a few keys that are broken, which I have ordered, but also has 6 missing notes across the board. These are not the same keys as the broken ones. I have reset it to factory and updated the os. Does anyone know what may be the issue? Internally it looks clean, I even looked at the key contacts of these keys and they seem ok.

[maxpiano]

1) Check the flat cables connecting the keyboard to the mainboard (reseat them on both ends and ensure they have no bend that could have broken one of the wires)

2) check the diodes of keyboard matrix connected to those keys are OK