Berrien Springs, MI
Quoted from Frax:See, this is why I hate PCB *diagnosis*. I suck at it. Resistance test on that resistor shows correct value, but continuity test...ZILCH. Shows it as an open. Is that just because my meter is a 6$ POS or what?
Continuity is looking for -zero- resistance. On most meters, this test will not register anything over a couple hundred ohms.
You can test any 10 opto board (or any other variant) by pulling the receiver connectors off and jumpering the 12V pin to any of the other pins on that header. This will cause the circuit to trigger (BTW, be in switch test mode). If it doesn't trigger, then you can either assume a dead LM339 or start looking at the main board connector and the wiring harness.
Tony
