Hopefully a hypothetical assuming cannot repair a small SMPS in a 1U case.
Assuming 3 of those little "plug-top" , I don't know the generic name,
"phone charger" SMPS can have the usual fudge of changing 2 or 3 resistors
each to give +/- 15V, .2A and 5V , .5A and mains safety issues taken into
account. Would there be an EMC or cross-coupling problem due to 3
free-running oscillator SMPS running inside one box, often the case that 3
would be togrther in close proximity charging 3 phones at the same time.