Quick way to check if it's the chip wotto. While its in switch test remove the plugs at the bottom of the cpu
OK
So - to understand properly, I run a "Switch Edge" Test with the connector removed for the switch columns - yes?
If yes - what 'result should /shouldnt I get ?
Hi Wotto.
You need to remove the connectors for both the rows and columns, then use a jumper wire to simulate triggering the switches.
If you're not sure how to do this check Clay's WPC repair guide. (PM me if you don't have access to a copy)
You should be able to trigger the column 4 switches this way, if not then you have a bad U20 for sure.
