I’m posting this information in the hope it might help other folks troubleshoot if they have similar issues.
I came into possession of a Jackpot board (newest revision, black PCB) that had a problem.
The symptom is that incoming power to the board was a dead short.
In setting about troubleshooting this board, I first carefully inspected for any solder splashes, or obvious routing/isolation errors in the PCB exposed outer plane. Board / VMOT power has a fair amount of run on this board, so that was a logical pair of first steps. There weren’t any obvious issues that I could see.
Next up, I recalled that there have been issues where the headers on the Jackpot BOM ocasionally came from the supplier with pins that were shorted.
To inspect for this, I used a pair of right angle needle nose pliers and VERY carefully worked off the headers on the board for the TMC2209s, on the right hand side of each TMC socket. That’s the side that has VMOT and its’ ground adjacent in the Polulu style driver pinout.
Lo and behold- when I made it to the Y stepper position, there was a short in the contacts.
I very carefully bent these back to the correct shape, then reinstalled the plastic header covers.
It can be a little fiddly getting the plastic covers put back on, but I succeeded.
If I’d messed the header up, I was prepared to de-solder it and solder in a new one.
Thankfully, this was not required.
The result is a happily working jackpot.
Ryan’s test process catches nearly all such mistakes, and he recently changed the BOM to use a different header that hopefully doesn’t have this happen at all or at least not as often.
A note that even though I was careful, it’s pretty easy to make nicks in the plastic- but even though I made a couple of nicks in it, this board passed a test just now and will be joining a couple of other Jackpots that I have as test boards.
Edit to add- Yes, I see that there isn’t perfect solder fill on that header, in at least two places. The other headers were similarly not ideal. If I ever have problems with this board in the future I might elect to pull and solder in new headers at any position that has trouble.