HP-67 Card Reader became very touchy

[Alevin]

Her comes the update.

Finally I desoldered the suspected bad 47 nF capacitor. The measured ESR was about 2,7 Ohms, and the capacity was out of range. So for sure it was kaput.

I manage to insert a new tantalum 47 nF 25 volts, Bulk packing. 14 € each, not cheap thought. Even the diameter was larger than the original, and it barely fit in to the remaining space, it quit fits in the holes (staight "legs" 5 mm spaced). Ref is a KEMET 350K476K025AT. Measures out of the board were 45 nF, ESR 0,01 Ohms.

And It worked!!. The HP 67 started reading cards OK at first chance, with a fully charged battery. Great!!

Thanks all contributions. The subjet should have a permanent pushpin as is a common issue.

This cap change should be recommended at first instance when card error appears once repaired the gummy wheel, even before try all that kind of mechanical fixings, that mostly have no effect, or end in a mismatch of factory fitting.