FSH6 FSH3 schematic or layout

[Xyphro]

Hi!

A friend of mine (without internet) has an R&S FSH6 where some keys on the keyboard are not working.
We checked already the keyboard, but there are no broken wires. They make well contact, even when testing them down towards the connector on the PCB. The resistances of the keys when pressed is rather equal for all keys. After long analysis we think, that there is something broken on the PCB.

Unfortunately the service manual does not contain any schematic or layout, only a component placement diagram.

Does maybe somebody has some more details like schematic of keyboard to main IC connection or similar to enable us to debug further?

Best regards,

Kai

[Xyphro]

Or: did anybody probe the switch matrix connections and can tell me which connector pin has to make connection to which IC pin? :-)