also, many units derive low voltage from the flyback when it's
fired up. I have found in some cases where this voltage gets
rectified, the filter caps are bad.. and other times, devices
connected to this source are shorted..
the main PS unit also may monitor this source to know when to
shut down the unit if voltage is gone or never gets there after
a couple of sec's

Thanks again. Iv'e checked every cap in the PS and all good. I'm sure
the main PS isn't the problem. Iv'e also checked several other
electrolytics, and nothing yet. Again, without a manual or schematic,
I can only check each component as I go. This may be beyond my
capability, but I'll reply after the flyback test - even though I was
told by a tech this can give false results. Thanks again.