IGT I Game 3902 board give touch screen comm error .

[jasonhieu]

I have a 3902 board for my IGT I plus game that give a touch screen comm error .  I thought it was the touch screen len and touch screen controller at first but I put that same board into a difference machine that works and it still gives me that error .  I tried to clear ram and reset it but the touch screen doesn't response .  Anyone have any idea what on the 3902 board that might be bad ?  I use another board with the same chip set and it works fine .  It's something on the board that is not working .

Any help would be appreciated .
Thanks for your time .

[idesign]

Have you checked the board connectors for a bent pin.

[jasonhieu]

yes .  I did check all the connections and none of the pins were bent .  I'm able to clear ram and get it to go up to the kep chip menu .  But can not configure anything in the menu because the touch screen doesn't work .  After a minute the system reboots and then comes up with the touch scren comm error .

Any advice anyone ?

Thanks.

[jasonhieu]

Does anyone know which chip or circuit on the board that controlls input to the touch screen or touch screen controller ?

Thanks.

[Tilt]

The touch screen controller is a Netplex device.  There's not one, but several components that make up the Netplex circuit on the MPU board.  I've attached a page from the MPU schematic diagram that shows the circuit.  I'd start by making a physical inspection of those components.

[jasonhieu]

Thank for the reply guys ... I downloaded the schematic diagram and will look at it tonight .  Tilt, is there a particular place on the diagram that the Netplex device is located at ?

Thanks.

[Tilt]

Around B4, Netplex TxD and RxD.