HP-67 Card Reader became very touchy

[Alevin]

(09-26-2023 11:18 PM)Alevin Wrote:  

(09-26-2023 10:55 PM)teenix Wrote:  Apologies, crossed wires on my part :-)

I had posted this HP-67 capacitor location image before (not sure where) but here it is again.

cheers

Tony

Great, I could not find this usefull pic.

Mesuring on the circuit the ESR it gives a 2,7 Ohms vaule, that is a large one for a 16-25 v 47uF cap.

So I will procede to serarch for a tantalum 47uF 25 volts or 16 volts.

I will inform on the results

Thanks a lot


Ricardo

Thanks you all given great tips and advice.

Looking for replacement tantalum cap for the power line, as indicated: 47uF 16 or 25 volts, I have found in present catalogs (KYOCERA, KEMET,...), they have a dip diameter aroun 9 mm, whereas the original is about 4,8 mm. So they will not fit in the tight space around the cap in the HP-67 PCB.

May be I am missing something? may be there some particular specification I should look for?

Thanks in advance.