OK, so the new board is here. I decided to use the 12V power supply I bought on amazon instead of the adjustable one just to be on the safe side. I cut the connector at the end of the cable and connected 2 pairs of cables that came with SKR pro board in parallel. One pair for the board, another pair for the motor power.
I tested the polarity with a multimeter 3 times. Multimeter showed +12.27V. Just to be on the safe side, I thought i would connect the new PSU to the old toasted board to check if I see the 12V led and if I don’t burn anything with the new PSU. To my surprise, as soon as I plugged in the PSU, one of the 2209 drivers smoked happily.
Okkkkkkkkk. So now I am getting a bit paranoid. Lately every time I power up the board, I see some smoke going out and it doesn’t smell nice 
Why did the driver burn? My ideas:
- The toasted board didn’t work as expected because it was damaged previously?
- The bent/disabled end stop pin could in theory be touching the capacitor under the driver? No idea of this would be an issue.
Some questions before I power up the new board…
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Is it OK to power up the board with the motor drivers in place and motors disconnected?
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Is it OK to connect board power and motor power in parallel from the same PSU? (see the pic)
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One stepper driver is obviously out of order, the others don’t show any signs of being damaged. But I don’t know for sure. I am thinking if they are damaged and I connect them to the new board, I could damage the new board, which is something I am trying to avoid now.
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To replace the broken big tree tech TMC2209 v1.2 driver with an identical one, I would have to order it from amazon and wait until the end of next week. Local shops have TMC2209 v2 here (see the pic). These are probably manufactured in China. Is it OK to use it instead of the original one?
Board PSU connection pic:
TMC2209 v2 I can get locally:
thanks