I have a OPUS BT-C3100 V2.2 that boots up, detects batteries in all 4 slots, cycles through modes, displays voltages accurately … seems to do everything EXCEPT switching into the selected mode no matter how long I wait.
When the problem originally started occurring (not long after I got it), I could usually restart the unit or cycle through modes and it would eventually kick over into the set mode and charge (or discharge/test/etc) normally. It seemed to get more problematic over time and now won’t switch at all.
I don’t see anything obvious … bad solders, burnt components, etc. Not sure how to revive it or what to try other than junking it and starting over.