Brian2

Yes we have just had that problem. We had a major power outage ten days ago which lasted longer then the UPS batteries that we have. Therefore the system went down comletely.

Since then we have had at least three shelf power supplies go faulty. The UPS seems to be OK, other than the voltage it is supplying is 53v not 50v.

Does anyone know what the voltage range limits are on these shelf power supplies. The installation lit just says -50v, but surely there must be an operational range.

At least we know we are not the only ones having failures after power outages.

DXHLS

This is a known problem - If possible, I suggest that powering down the telephony shelves on a rotating basis by removing then reinserting the input fuse on the PSU will minimize the failure of these supplies (they only seem to fail if they have been powered up continuously for a long period). We have implemented this into our planned/preventative maintenance procedure that is in place when the field techs do a site visit. This is normally done at low/quiet traffic times depending on the customer.
Otherwise just make sure that you have some spares readily available.

The Product Guide gives the following spec - DC powered systems require a Nominal 48V DC (-5V / +10V)