HP 65 - top row of keys not working

[Frank Balzer]

Just acquired a HP 65. Unfortunately the top row of keys (i.e. A - E) is not registering. All other keys are working. I opened it, but didn't find any obvious problems such as corrosion. Any ideas?

Frank.

[Ignazio Cara (Italy)]

Look at the connection betwen logic PCB and Keyboard/display PCB, pin number 11 looking from the right side of the calculator up side down. Perhaps you could find some sign of corrosion or the pin could be broken.

I hope this could help you.

Regards

Ignazio

[Frank Balzer]

Thanks for your suggestion. I'll try to clean it with isopropanol next week. However, optically all the pins look very nice. No corrosion, no bending, nothing.

Regards, Frank.

[Jeff O.]

Individual keys that stop working can often be remedied by cleaning the contacts as described in this post. While fairly unlikley (I suppose, I am not a statistician) for five keys in the same row to suffer the same problem at the same time, it might be worth a try.