HP 65 Card reader task

[teenix]

There is some info in my Classic Notes pdf download.

If you adjust the leaf springs make sure they are sitting up the same amount or one could operate out of sequence and give errors.

The large hybrid chip on the CPU board controls the card reader. If you have a working 65 then try swapping the CPU boards between the two calculators and test both. It will quickly eliminate any problems if the board is the cause of the fault.

If the fault persists with the swapped board and original faulty reader, then it is hopefully a connection problem. Check the pins connecting the small card reader board for corrosion, and any wiring attached from the motor and battery.

If this checks out ok, then the sense chip may be faulty. You can only test this by substituting a good sense board or swapping the IC with a good one.

While fiddling with the disassembled calculator you may damage the connecting wiring at the top of the circuit board near the displays. Page 48 of the above notes has a picture showing what can happen.

cheers

Tony

cheers

Tony