HP-67 Card Reader & Sense Amp problem

[mikemorris]

Thanks Tony! I think your diagnosis makes sense. I'm going to try replacing the caps. I read someone's comments in which they were surprised how much doing that helped in another situation. However I also suspect the sense amp chip itself. Thanks to the Teenix logic board I don't really need the card reader, but amongst my personality defects is a strong discomfort with any machine which is not entirely functional regardless of whether I need all the functions ;-)

Does anyone have thoughts on where to find one of those sense amp chips? Presumably a donor calculator? Obviously another HP-67. Are there other models which could also be a donor?

-Mike-