On Mon, 15 Mar 2021 00:53:59 -0400, Paul wrote:

| Rene Lamontagne wrote:
| On 2021-03-14 5:01 p.m., Bob F wrote:
| On 3/14/2021 1:27 PM, Larc wrote:
| Symptoms: started rebooting occasionally, progressively increasing
| with prior mouse
| pointer fadeout or freeze (cordless and corded mouse) - stopped
| seeing USB wifi
| adapter, although USB drives would still work - now won't post at all
| (power comes on
| and case PLED and fans run for about 20 seconds, then reboot, rinse
| and repeat) - no
| HDD LED - no signal to wake monitor - power to DVD burner on.
| Multiple reconnections
| and even reseating of the CPU and heatsink/fan and trying different
| memory modules
| didn't help.
|
| PSU: Tested thoroughly with comprehensive digital PSU tester and
| everything 100%
|
| Is there anything else I should check out? I'd like to learn it's
| not the
| motherboard since a replacement that could accommodate the 7th
| generation i3 CPU in
| it would cost about as much as a new 300 series board and i3-9100 CPU
| combined.
|
| I'm not running a higher powered setup here since this isn't a main
| system, but one I
| use for Windows Insider development testing.
|
| Motherboard: ASRock Fatal1ty H270 Performance
| PSU: Corsair CX500M
|
| Larc
|
|
| You tried replacing the battery, and resetting the bios? If it comes
| up enough to do so, re-burning the bios could be worth trying.
|
| Sometimes power PSUs test great with a tester but do not deliver clean
| power under actual operating loads, It may be worth trying another known
| good PSU just to make sure, otherwise the MB is probably the culprit.
|
| Rene
|
|
| Remove PSU cover (voids warranty), look for leaking caps on +5V rail,
| do not touch anything. Look at it only. The PSU is likely well past
| the warranty period, in which case stealing a look won't matter.
|
| If we knew the brand of PSU and model number, it would be
| possible to guess at this. Antec made by ChannelWell (CWT)
| are known for this. I have several duff Antec in the
| junk room. Other brands have treated me better.

I included that at the bottom of my OP. It's Corsair CX500M. And it is out of
warranty.

| With some luck, a puff of gray smoke comes out
| of the PSU hole at startup. Once the +5V caps warm up,
| the smoke stops.

No smoke or tell-tale acrid smell. But rather than opening this PSU, I'll wait for a
new one due Wednesday that I can put in temporarily to see if that makes any
difference.

Larc