HP-67 1705A01234 [erase other's cards, writes and sometime read back its own cards]

[teenix]

I learnt that the card switches can be finnicky if the chassis is distorted or if they are not adjusted properly, probably from bent contact fingers. These problems might upset the timing of the switches and confuses the CRC.

When the keyboard PCB is positioned in the front panel, it should sit flat on the mounts that are moulded into the front panel with no rocking. If it doesn't sit flat when the screws are tightened, the assembly will warp and put twisting forces on the switch contacts.

Sometimes the power wires can get in the way too.

cheers

Tony