Thank you Avidcomm. It looks like you nailed it. The local vendor has informed me that they had the issue diagnosed by a local agency and it seems that some of the electrolythics are drying out and preventing the PSU from restarting. I'm now upto 8 failures this year. Two came back after about an hour when removed them from their system. I've asked for more specific information (ie which ones) If they tell me I'll mail you directly. Tadiran have nothing to say on the issue. Thank you all for your input.
Regards, 63.
