Computer mysteriously seems to power on after surge, but no video or network

Question

I have a box running Linux Mint I've been using as a file/plex host for about half a year to a year. Last night there was a brief power outage and I shut down both of my PCs (linux and Windows machine) using the power switches on the front. They were both running just fine on the heavy duty UPS I was running

Now the Linux box seems to give me a flashing HDD light as if it's booting/running normally, but no network. Ping to the box is unreachable, so is SSH, VNC, etc. I had been using it headless with VNC as the only control for quite some time.

I also have no video out regardless of what I plug into the damn thing. I've tried two different monitors and both DVI and HDMI ports on the motherboard. So I have no way of telling if the machine is really running.

All I can think is the board is at least... partially fried? Which is disturbing because it was on a surge protector/UPS with the other PC. I can't imagine why the power switch and HDD lights are running if the motherboard is dead. Would it power on fans and make the HDD lights flash with a burned out motherboard?

It never really made POST noises, not ever. It has a UEFI and has always started up and run silently.

This is the hardware but I don't know if it's relevant:

AMD Quad Core A10-Series APU for Desktops A10-6800K

GIGABYTE GA-F2A85XN-WIFI Socket FM2/ AMD A85X/ DDR3/ SATA3&USB3.0/ WiFi/ A&GbE/ Mini-ITX Motherboard

Answer 1

General answer is this: if you have UPS, then you should not have a surge in the system, and consequently no damage to system from brief power outage.

My experience tells me that electronic and/or electric devices (that is: basically anything pluggable to power outlet) do not like fast off-on sequence, especially repeated. That's why you should always wait before switching anything on after turning off, at least 5 - but best 15 - seconds.

I'd say that your computer lost power momentarily and because of that trace currents in the system (and capacitors and such) did not fully dissipated/drained from the circuitry. Which is impossible, since you stated you powered down the PC manually.

So answering your question: yes, it's possible. Seen it on lots of Dell machines in my time as DCSE: power on, lights up, fans on but nothing came of it. This is usually indication of faulty mobo (but PSU as well, unfortunately, and rarely the power switch itself...). But Dells have built in self-diagnostics of some sort of other and usually LEDs blink or give steady light in a sequence which is an error code. Look up system/mobo manual - maybe there you'll find something.

The other possibility is that some attached device is causing a short in the system. Seen it as well. To find out disconnect anything not needed for mobo power-up test (VGA on PCIe, HDD's, ODD's etc.). Just connect PSU, power switch, CPU, ram, and external monitor. If it powers up then you have something disconnected faulty. failed HDD can do what you describe as well.

Only comment on the situation is this: you had really bad luck, as quite possibly the power outage and PC failure are just coincidence.