HP-67 Card Reader became very touchy

[John Garza (3665)]

(10-17-2023 09:37 PM)Alevin Wrote:  My limited electronics knowledge is nevertheless enough to know that the capacitance value of caps measured when soldered on the PCB is affected my surrounding circuitry, and it can not be taken either as the real value, nor indicator of the cap condition.

Always best to test components when extracted.

However on the overall picture...

Well... if you have time on your hands, this seems a reasonable path.

Otherwise... keep in mind these caps, even if good now, are likely to fail in the future.
So... while you have the machine apart, try some preventive maintenance and replace them now.
Don't test, don't ask, just replace them all.

But then I'm biased as I'm older (60's) and don't want to have to go back in there years later with weak eyes and shaky hands fooling around with a soldering iron !

Build (and repair) to last. It's an HP thing.


-J