Weird UPS/shutdown issue with my mom's Mini

[PeterB]

Hi guys, my mom has an older (but usable) Mac Mini which is hooked up to an older (but usable) APS UPS, as we get occasional power outages here. She's running the latest version of El Cap and I have set up her Energy Saver settings so that her machine should be gracefully shutting down after it's been on the UPS power for 3 minutes. I've also checked the box to automatically restart after a power failure.

What happened this morning, sure enough we lost power for an extended period, and when the power came back on, the Mini had not restarted and the machine would seemingly not boot. We had to boot by pressing the Power button for a longer time. After that, I did a test by unplugging the UPS to see why what happened happened, and what it did was: rather than gracefully shutting down after 3 minutes, it just shut off completely. Before it did, the percentage on the UPS was still in the ballpark of 95%. (If not for that, I might have thought the issue was the UPS battery, but I replaced it last year IIRC.)

Anybody know what's going on here? I hate to be doing troubleshooting of this kind, especially today of all days, but I won't be home long and need to take care of this sort of thing before I leave.

TiA

[Onamuji]

Zap PRAM and see if the issue persists.

[S. Pupp]

Also, while UPS is unplugged, disconnect its battery for a minute or so. If there is a problem with the UPS, this may reset it.

[GGD]

Test the UPS by itself with a lamp and real 60-100W bulb, or similar load and see you can unplug AC , if the UPS is really good and withstands a 10-15 minute simulated "power failure" and recovers when power is restored, then focus on the Mini.

[C(-)ris]

UPS might be shot but it reporting bad info to the Mini.

[PeterB]

C(-)ris wrote:
UPS might be shot but it reporting bad info to the Mini.

Yes, that's what I thought might be going on... I haven't tried the other suggestions in this thread, but will when I get a sec...