D button doesn't work

[Porthos]

Hi all.

I have a problem with my NeoGeo control pad. Suddenly the D button doesn't work. The button works flawlessly with others PCB's that I have, it's only with my MV-1FZ base the button doesn't work and only in player one, in player two works perfect
On the I/O check screen all the buttons works fine, number 1 appears when I press each one, but the D button doesn't.

Any idea?

 

[Apocalypse]

Either:
- dirty edge connector
- severed/corroded trace
- faulty pull-up resistor
- faulty input on the chip handling controls

 

[Porthos]

Thanks for the quick response.

OK, do you recomend new resistors? I never was do it but it seems easy.

Another question. The board is a little dirty and I would like clean it. What product is the best for that? Can I use Cillit Bang or KH-7?