HP-67 Card Reader became very touchy

[teenix]

The HP-97 capacitor that matches the one that you changed in the HP-67 is marked on the attached image as C6 - 47uF. The image refers to later model 97's, earlier ones have the parts in different places.

C6 - 5V Battery bypass
47uF, 16-25V Tantalum

C4 - Vss (+6V filter)
22uF, 16-25V Tantalum

C2 - Vgg (-12V filter)
68uF, 25V Tantalum (Not sure what the original type was though)

Note the polarity of each as they are polarized and inserting new ones the incorrect way will damage them. (Lots of unpleasant smoke).

Also note that the HP-97 service manual has the +ve marking for C6 to the top of the capacitor, but it should be to the left side as in the image as the capacitor pins are horizontal not vertical.

cheers

Tony