As for the 2530s, it's assumed they are being powered via a 24VAC source. As for the other 2500 series cameras, are they being powered via PoE, or via a 24VAC cable plant / transformer as well?
If they are all being powered via a discreet 24VAC source, what other information can you provide with respect to the transformers? What is the VA rating of the supplied power? Are the cable lengths excessive? Cable gauge adequate to compensate for voltage drops? Is the 24VAC on filtered or UPS based power?
We have a situation where a facilities external 2530s are on (via a 24VAC transformer) a questionable source of AC power, and on more than one occassion when the facilities deisel generators are tested, these cameras can end up in the state you described above.
Bulletproof Solutions Inc.