[SOLVED]820-3115 - 1 and A keys not working.

[Alan.L]

I've tried over 5 keyboards, new, old and it is always 1 and A key isn't working. J5713 connector looks very clean. can't see any corrosion inside the connector nor on the pins. U5701 looks good as well. all other keys are working.

i can't see any corrosion on the logic board.

any idea? bad U5701?

 

[2informaticos]

I don't have any idea how the matrix rows-columns is realized, but is very strange to have only 2 non-working keys.
Should be more keys affected, if one row, or column is bad.
Maybe some function keys (upper row of keyboard) are not working too.
In such case, you suspect a row, or column.
One key, or few only, is normal keyboard problem; individual keys issue.
Did you try PRAM reset, just in case?

 

[Alan.L]

let me run some test, get back to you. no, I haven't try PRAM.

 

[Alan.L]

you are right, i thought Q and Z was working. now i tested 1, A, Q , Z, f11, f12 doesn't work.

 

[Alan.L]

I'll do the continuity test from J5713 to U5701 in first thing tomorrow.

 

[Alan.L]

fixed. 1 of the WS pin on J5713 had no resistance to anywhere at all, so I touched up all the pins on J5713 and U5701 with fresh solder.

 

[dukefawks]

Be aware that U5701 is a pretty princess and sometimes has intermittant failures. So this one may return, replace U5701 if it does come back.