Picked up a dead alien poker recently, I finally got it working ( a big thanks to Barkandl for the 5101 Ram) but it has an issue with the drop target switches not reading, everything in row 2 of the switch matrix is dead. the drop targets were in about 20 pieces when i bought the machine so i replaced the whole bank with one from a jungle lord thanks to a heads up from Winteriscoming. He is using this in his alien poker with no problems. I double checked all of the wires for every switch on row 2 of the matrix from the switch to the connector on the board and all are good. I also checked all of the diodes and they are all good, I did find one that was bad and replaced it.
next i pulled 2j2 and checked for pulsing with a logic probe and all pins were pulsing. (which I'm told is good)
then i pulled 2j2 and 2j3 and checked the pins on 2j3 and there was no pulsing (which i am told is good)
then with 2j2 and 2j3 connected i put my logic probe on pin 8 (for row 2 of the matrix) and started making the switches in row 2. I am told i should see a pulse every time a switch is made. I did not see any pulses when i made any of the switches in row 2 of the switch matrix.
so i know the whole row has a problem, i just do not know where to look next. I cannot find anything that points me to a specific component to test.