Mitsubishi Fr-sf-2-26K. Top board SF-CA. Option card SF-BS. The original problem was a dead power supply after running the night before. Replaced PS, then found shorted IGBT in base. Replaced IGBT. Started getting Alarm 23. We tried the top board (SF-CA) on another base; it worked. We had motor checked by motor shop and also megged it out. We put drive in open-loop; it still won't run. We tried another sensor/PLG card; no good. The only thing I know thing know that is left is the SF-BS card. I'm not sure what all this card does. We do not do orientation. I have not ohmed out cabling, but do not think this is the culprit. I may try the other top board out of the good unit but did not want to chance messing it up.
Any thoughts? I hate to send this thing to Mits, but that may be next.....