HP 67 slider switches and trace trouble

[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