HP 9825 keyboard restoration

[Paul Berger (Canada)]

(02-25-2017 01:14 PM)Tom Ward Wrote:  Frederic,

Did you have any luck finding a suitable replacement for the switches?
I've a new to me 9825T that is in need of a replacement switch.

Thanks,
Tom

I went down that road not to long ago, the keyboard I was repairing had water that had leached through cement drip on the keyboard and it was a huge mess. Water had got inside several key switches, and corroded away internal components others where contaminated with lime so there was no easy solution for them either. I ended up replacing a number of the switches with ones I had salvaged from the keyboard of a 4972A. They fit into the keyboard nicely but the stems are slightly longer and the cross on top is a bit smaller. I used these switches for the numeric keypad and the switches for the top two rows, because while there is only a slight difference in the length of the stem, if they are mixed it would be noticeable. To make the keytops fit on tight I initially used strips of paper as shims, but later switched to narrow strips cut from a pink static bag. These shims hold the key top on tightly with no wobble. I do not know of any exact replacement other than a keyboard from a 9825, 9831, 9835 and lily also a 9845.

If you plan to desolder and reuse a key switch be careful , don't go crazy with heat, but make sure you flow the solder before you pull on the switch or else you may dislodge elements in the switch.

Edit: This applies to the keyboard with the full stroke keys only, the early keyboards used an entirely different switch.

Paul.