3802 igame with no button response

[Melissarmdlm]

I am working on an iGame 3802, this machine is significantly older than my area of expertise so I thought I would ask here.
The machine appears to boot as normal, but the player cannot use the button panel at all. No lights, no response. This behavior carries over into the diagnostic screen which presents like the picture below. All io's locked on "1" throughout the cabinet.
As part of troubleshooting, I installed a 3902 in this cabinet and curiously the button lights are responsive in diagnostics, but deeply and randomly flickering, and still no response to button presses. Spin has the I/O boards for these old cabinets in stock, but I'm loathe to acquire one without some further insight into whether this in an I/O board problem, or something else.
Other diagnostics I tried were PS swap(no change), and unplugging each of the three i/o harnesses: button, coin, lights. No change in behavior for any of the harness plugged in combos.

[Tilt]

I'm not sure why the the symptoms are slightly different between the 3802/3902 boards, but either way it sound like the switch panel I/O panel board has failed to me.  It's the larger of the two boards and here's a schematic diagram for it if you want to try to trouble shoot it to the component level.

 

[Melissarmdlm]

Thanks for the schematic, I'll investigate if some of the more recent i/o cards that there are boxes of to see if I have some chips that can be borrowed for transfer to this old board.

[Tilt]

Many of them are the same.  Others are probably still available from Digikey, Mouser, or other electronic part suppliers.