A500 weird keyboard problems

[xalakibaniou]

Yesterday I took the amiga 500 out of the attic and thoroughly cleaned it inside and out. I didn't see any signs of corrosion. i?'s a revision 6.
Everything works fine except for F1, * and + on the numeric pad
As it loads the workbench 1.3.2 by pressing the + and * keys it does not display characters. After loading the workbench I open a cli and I can write any character except for F1 the rest of the F keys display this character ~~ which I think is correct.
Same key problem when i load Xcopy (cant display * and +) for example when i format o disk and asks for a name or a trained game which asks to press F1 (an i cannot obviously).
I forgot to mention that keyboard layout is UK.


So far: I have opened the keyboard I have cleaned the membrane, I have looked at the pcb for any corrosion and defects. What could be wrong?

[solarmon]

If you are sure that there are no trace breaks then you can try the following.

Use a bit of aluminium foil wrapped around your finger and test the carbon pads for the suspect keys.

Alternatively, use a known working plunger from another key.

If the above work then the issue is the plungers for the suspect keys.

You could try cleaning the rubber carbon pads. What I do to fix plungers is to use copper foil tape (type used as slug repellent) cut to size and put on to the rubber carbon pads, with a bit folded over the ends to make it more secure.

Meanwhile swap the plungers for lesser used keys.

[xalakibaniou]

I noticed a worn trace at F1 key on the membrane. I switched the membrane with a spare one and it's working now.
Thanks for your help

[solarmon]

You can fix the trace using silver conductive ink.