For the city I work for, all of the Astrotac Rx sites are using 115Vac with backup batteries (just in case). For years they showed no signs of aging until recently. When we had a receiver on the bench for testing, we found that the unit would reset itself every few minutes or so. When we attached 13.8V to the battery input the unit stopped resetting.
Looking closer we found that when the power supply was plugged in, it would leach some power from the batteries to keep itself alive (about 800mA). A known good power supply did not pull anything from the Battery.
We sent in the board for repair (CLN6959A), and got something of a run-around. We received a working board back from the depot, but it was clearly not the same one that was sent in. The parts they said they used are no longer available (and haven’t been for sometime).
The problem we have is that almost ALL of the receivers we have are pulling some amount from the batteries (200-500mA) indicating that they are beginning to fail. At $645 per board repair, we are looking at almost $13,000 to repair them all!
Now for the big question. Would any of you fine, educated and experienced bat labbers have any experience with switching power supplies? I would like to learn how to repair them but I can’t seem to find the schematics anywhere.
Thanks for any and all input,
WEC
[EDIT: Spelling]