Read?Write HP 67 card reader

[John Garza (3665)]

Hi Geoff,

Good job!

The problem you describe is usually caused by capacitor A (the 47uF one) in your picture.
But as usual, it's good to replace them ALL once you're in there as preventive maintenance.
And HP solder lands have little squares for the positive leads, just to make it easier. The old caps themselves usually have a little dot painted on the positive side.

Also, I know it's practically canon to use wire insulator for the coupler replacement. But I've found an easier way. Just dig out all the remains in the cylinder sleeve. Pack it with RTV gasket maker compound and re-assemble the unit forcing the motor axle down through the goo. Then use needle tweezers to clean up any spillage. Let dry overnight. The result is a rubber-like replacement. Voila!

-John