Re: UPS Turnon Brief Short: Help?

Proximate cause:

Watching the FET gates shows a good pulse. So the problem is on the output
side. There is a transformer winding I assume is feed back. It goes to a bridge
rectifier. This rectifier is "fused" with a 1/4 watt (that size anyway) resistor.

This 2.2 ohm 1/4 watt resistor used as a fuse was toast (and open too).
I believe it was 2.2 ohms but the bands were pretty burned. It is labeled F1. I replaced
it. The UPS seems to be working now. With a 60 watt bulb my battery stayed...

A UPS problem:

When reset (AC line power connected or not) the Battery Power comes on
for 800ms then goes off.

I have checked the ESR on all electrolytics. They're fine.
I have two different batteries and the problem with each
installed is the same. Both batteries are of the correct size
and at full charge.

I have attached two waveform files for the AC output. They should be
a clue. Something briefly shorts the waveform but then stops partway
through each cycle. This problem occurs on both the positive swing...