I am assuming something here, and that assumption is that you have more than 1 carrier. If I am wrong, then please correct me.
-BROWN OUTS-
A lot of the times, when power goes out, you have a problem of an improper "BOOT UP" due to a mish-mash of Power Units.
Here's the deal, some Power Units come up faster than others.
Remember, the proper way to power a system up is to power up the RIGHT MOST SLOT first, and then the NEXT LEFT and the NEXT LEFT after that. (If you have 3 carriers)
Thus, if you have a "FAST" POWER UNIT in slot 1, and a "SLOW" one in slot 2, slot two will come up AFTER slot 1, therefore you have the problem.
The problem being, slot 1 won't see slot 2, 'cause it came up "LATE".
I really can't remember which ones are SLOW or FAST, but it can easily be proven by turning off the "SOURCE", and then when it is turned back on, observing which POWER UNIT comes up first.
But, as I said, if you only have one carrier, I am all wet here.