a_wookie
Member
i have a system 11b game that i am having a issue with. i noticed multiple switch problems so i put the machine in switch edges test mode and cleared all the optos/through. At this point there is no closed switch's. if i close any switch in column 3 i get a message " short to ground row 5 wht/blu ". this will be whatever row the closed switch is in.
this seemed that i had a switch column short to ground, but i carefully checked the column and nothing. so at this point i decided i needed to isolate if it was in the head or the cabinet.
My next step was to remove conectors 1J8 1J10 (switch row and column).I then put a diode in a test clip and bridged the matrix manualy to see if my issue was in the mpu.
Sure enough i am still getting the short to ground error on column 3.
schematics showed Q44 drove column 3 but i tested Q44 and its good.
so my question to anyone is, what should i try now? u40?
thanks in advance
this seemed that i had a switch column short to ground, but i carefully checked the column and nothing. so at this point i decided i needed to isolate if it was in the head or the cabinet.
My next step was to remove conectors 1J8 1J10 (switch row and column).I then put a diode in a test clip and bridged the matrix manualy to see if my issue was in the mpu.
Sure enough i am still getting the short to ground error on column 3.
schematics showed Q44 drove column 3 but i tested Q44 and its good.
so my question to anyone is, what should i try now? u40?
thanks in advance