Need some help ...!!

[mike111]

I'm working on a board from a poker machine that used to work till the edge connector came loose n sold back and forth on the board edge..... After that only the bet and draw buttons light up...... After playing n digging around with the scope on this board I've ran Ito a few strange things......... The button lights that are not on are being supplied with voltage on both sides of the bulb....... I changed the most common chips already 7404 ect ...... Checks all diodes and confirmed daughter board function on a similar game....
After further poking around I found the when the (2) D8255ac-5 chips are partially inserted in just the correct position all the button light as they should .... Should I suspect these chips or something before or after them ????  Which chips inserted fully it flashes gray on the screen ...... I haven't been Able to see what it does with chips partially in cause I have the mon chassis out , I'm going over that as well...... Any direction as where to go with this board I'd greatly appreciate........ Where to poke n probe n what to look for ????? If I were to replace the 8255's will I need to program them for this game setup ???
Thanks

[asgard]

Some of the ports in the 8255s probably stopped working, it is important that you change them and not switch them around or you will solve one problem and end up with another. You can just replace them, they do not have to be programmed.