HP-67 Card Reader became very touchy

[teenix]

(10-21-2023 12:13 PM)Alevin Wrote:  More over, the indicated diode (CR5) in the pic attached, tested on the board is conducting in direct (700 Ohms) and inverse polarization (1.400 Ohms). Is this correct? The same happens is measuring the resistance on diodes on the main PCB in the area of the card reader (CR1, CR2, CR3, CR4)

I measure normal diodes across all of these. Do you have the multimeter set to Diode check?

If you don't have a solder sucker, and you need to test them out of circuit here is an easy way to remove one end without overheating the part.

If you have some small gauge wire (Eg telephone wire) bend a small u-shaped hook on one end of the wire. Hook this around the wire of the component end you wish to remove. Hold the soldering iron with slight down pressure to melt the solder from the component side. As soon as it melts, pull on the wire, the component end will come free, then remove the iron.

You can then clear the hole out with solder-wick from the solder side. If the component tests ok, just push the component end back in and re-solder.

Careful with static when handling the board.

Good luck

Tony