San Antonio, TX
I was getting a check opto 1-4 problem during test as well as ground short row 3-7. I replaced U1 and U2 (LM339) on the opto board, no change. Checking with an oscope, I have hi with pulses coming in on the green. Each of the outputs for U1 and U2 go hi when the opto is blocked. Replaced the opto sensor boards. Cleared the check opto problem but, I still have a ground short on rows 3-7. Changed output diodes, no change. Have U1 and U2 socketed and have changed multiple times. Checked values on all resistors. Changed 12VDC capacitor. When I unplug the rows from the board the problem goes away. Opto 5 works fine (Thing flip). At my wits end here. Please, help.
(Topic ID: 204355)
Auckland, NZ
Vancouver, BC
