seems as a plausible explanation, as the the power cut only involed one of the two powercords.
Can you confirm that all 3 fans on the PSU spin just fine?
icould try with a psu from a T17 40 Th would that be sufficient for the test of the faulty T17+ 58th?
NO, don't do that, the T17+ uses APW9+ while the T17 uses APW9 EMC, I am not the right person to ask when it comes to electricity but my guess is that the APW9+ could damage your T17.
Upgraded to latest Bitmain orginal FW, and now flashed the awesom SD 2.03.
Are you getting different results?