HP 67 slider switches and trace trouble

[jftman]

Please see the pics. Looks like a break on the on orr side and some partial missing trace along two traces on the run/program side.

How do I clean and grease the switch sliders? To begin the job.
Next I think I would close the on off break with a conductive silver pen carefully and let dry.
But since the other side has some missing but not all, I should not put the liquid silver 'ink' on there?
It would probably get rubbed away.

The calc does not turn on, except a few sparking bits, here and there but very very quickly leave nothing. I wouldn't even call them a segment. More like pin heads ofight.

Do you think the clean break on the on/off side will restore the operation?
Clearly there is rubbing on the left side that needs attention.
That is why I am asking how to clean and lube.....
Oooouch

Update.
Added pic after cleaning trace area with alcohol. Surprise that those breaks were not breaks. I will use Detoxit. What form of grease should I use?

[teenix]

Some tissue paper and isopropyl alcohol will clean it all up nicely.

You should replace it with proper switch lubricant, or if you can't, a "thin" smear of petroleum jelly. Don't leave it dry and use the switch or it will wear the circuit board traces.

The board itself looks ok.

Take care while manipulating the boards out of the calculator or the wiring may be damaged, See page 45 of my Classic Notes

cheers

Tony

[jftman]

Tony thankYou.
My one other autonomous action was resoldering the two wires back on.
The red one on the left is alone. The black one in the middle is one of three on that contact. The right contact is 'stock'.

Are those proper? I did notice the closeness of the solder glob to the neighboring board.
The wires became loose while handling the board when resoldering the black and red to separate the two boards in the repair routine.

I think I put the other ends where they should have gone, back where they came!

[teenix]

A somewhat awful soldering job.

Attached is the wiring for the 67 charge connector.

If you strip it all off and clean it up, careful with too much heat on the brass tube connectors. The plastic where they are fitted into may soften and the pins may move and won't align with the charger.

When re-assembling the middle plastic frame with the 6 screws, make sure it is seated properly. Sometimes it may not be and can warp when the screws are tightened.

The screws may have been in and out an unknown number of times, so when you tighten them, just nip them up, don't overdo it or the threads may strip.

cheers

Tony

[jftman]

Tony,
I did the gummy wheel.
I cleaned any corrosion found.
I replaced tge positive battery terminal from a stand alone battery charger.

It always acts the same way. Turn it on and a short display of a few bits of light almost instantly disappear.

I do not have an oscilloscope and the dc power supply I use for watch repair won’t turn on, sadly. It worked when used last?

This is now over my head.
I would be willing to send this 67 to one of the members here.
Of course You, if you would look at it.

Can you connect me ?

[teenix]

(11-24-2023 02:28 AM)jftman Wrote:  Can you connect me ?

PM sent

[mbielman]

Tony and jftman,

I am also offering my services. (PM sent on previous thread) I have repaired some 67s lately.
This sounds like a logic board issue. I can swap in a good one to verify. (I'm sure Tony could do this too, but I'm in the USA)

Mark

[jftman]

Email Sent.
Best regards.