We went through Step 15 Full-system Troubleshooting on page 12 of the manual. In the middle of the page it has a bullet that says:
Meter between pins 1 and 3 of X1, the large 3-pin connector. You should read open.
We measured 888 ohms. Checking the schematic, one pin connects to the fuse (AC neutral) and the other connects to pin 2 of rectifier D4 (AC hot) which is basically the two AC inputs of the rectifier so I would expect it to show open. We then went through the process of removing (destroying) the rectifier and installing the spare. It still measured 888 ohms. (Prior to installing it we confirmed that the AC inputs show open.)
Looking at the schematic more, those pins are also connecting to one end of the transformer that is used to power the electronics. Therefore, measuring between pins 1 and 3 of X1 should not be open and that's why we're measuring 888 ohms. It's the resistance of the primary. After this, I figure that the instructions are wrong and we're all set. All of the other checks passed.
We plugged it in and nothing happened after we increased the power for the interrupter. We determined that the phasing jumpers were wrong and rotated them. This time when we plugged it in, the fuse immediately blew.
We checked the board for bad solder points that could be causing a short. They are fine. None of the electronics appear to be blown. It seems that the IGBT bridge is probably blown. We will be replacing them tonight.
What I'm concerned about is why did they blow? I would like to avoid replacing them to only have them and the fuse blow again. Is there anything that we can check to help find the root cause? Is my analysis above about pins 1 and 3 of X1 not showing open correct and the manual is wrong?
Thanks for your help,
Stephen