Seeking keyboard for Compaq Portable

[Christopher Parish]

I actually just finished re-padding mine last night.  I struggled to find the right materials with the correct electrical properties, but I eventually came up with a process that works.

The mylar I had (conductive on one side and the plastic base on the other) wasn't working.  The plastic side did nothing and the metal side shorted the pins.  Out of frustration, I conformally coated the keyboard PCB with a thin layer of silicone (available at your favorite internet retailer), and now both aluminum HVAC tape and the mylar sheet (metal side down) work correctly.  I stuck with mylar because the aluminum tape tends to develop sharp corners and can scratch through the conformal coating over time.

So here's the stackup:

Double sided tape (3M 9474LE 300LSE)
Coarse open cell foam cut to height
Super glue
2mil thick mylar, metal side facing the keyboard

I used a 7/16" hole punch to shape each material.  The resulting keys feel almost the same as the ones I didn't re-pad.  Given the deterioration of the existing foam, I suspect that it's closer to the original feel anyway.

Hope that helps,
Christopher