HP-67 - 1612A03018 - Card Reader Advice Requested (was HP-67 - strange behavior)

[teenix]

Hi Alberto,

Seeing that [0.00] was displayed proves that the CPU worked properly, albeit briefly. Does [000] appear if in W/PRGM mode?

Swapping the CPU board if you have a spare one, would verify the rest of the calculator operation.

Because it was corroded and cleaning seemed to have stopped it working, as a start I would look closely at the circuit board traces, then the battery/board wiring terminations, and the brass link at the charge socket.

All that corrosion probably came from the pcb traces and washing the board may have degraded one (or some) a little more than the circuit can handle. Maybe some "gunk" ended up (or dislodged) under a chip, or a weakened component connection has now become a dry solder joint.

Probably a rarity, but board components can be damaged by static electricity during handling.

cheers

Tony