HP-71B Card Reader Failure

[TASP]

I have demagnetized items with a big 250 watt soldering gun, taking care not to burn anything with the tip.

(note the magnetic field is around the transformer, not the tip) And slowly drawing the gun away from the item works, and is a handy trick if you have a soldering gun and no demagnetizer at hand.

I've also used a soldering gun transformer for a transducer for an AC ammeter. Wire low resistance secondary with load. Put ammeter on primary leads. You'll need some way to calibrate it, IOW, translate whatever reading your seeing on your ammeter to an actual measured amp reading on the secondary load.

Caution, open terminals on transformer primary can develop EXTREMELY high voltages.