Momentary Power After Surge

Long time no see...

Windows 10 64bit
mobo: Asus p8z77-m pro
cpu: i5 of some description
ram: corsair vengeance 1600Mhz 8GB (2 of)
ram: gskill ripjaws 1600Mhz 8GB (2 of)
HDD: samsung ssd 128GB
HDD: WD sata 2TB
PSU: Aerocool xpredator 550w gold (replaced non-functional? coolerpower 700W)
no cards besides network


Had a power surge (very large bang, probably at transformer up the road), power went off and then straight back on, monitors and speakers still had power, but pc had none (all connected via powerstrip). operational light on powerstrip was non-functional. Neighbours reported having half/low power & no power.
Once powerline issue was fixed, everything else was fine, operational light working again on powerstrip. pc still dead.

Power led on mobo was not working after surge, so I replaced the PSU resulting in the power led working on the mobo.

When pc is initially plugged in/turned on at PSU, pressing the power button causes the power light to work (just and only for a split-second) and the cpu fan to turn briefly, no other signs of life.
pressing the power button again has no effect unless pc is unplugged/turned off at PSU and then plugged in/turned on at PSU.

Assuming mobo is detrimentally unimpressed, but hoping that is not the case as socket 1155 appears rare now so mobo replacement potentially means cpu replacement as well

Wondering if anyone understands what the momentary power response indicates?

Thank you

 

Unfortunately, it does sound like the 'board is the most likely suspect.

Disconnect all internal drives and external peripherals, try again?

 

"When pc is initially plugged in/turned on at PSU, pressing the power button causes the power light to work (just and only for a split-second) and the cpu fan to turn briefly, no other signs of life."

Had these symptoms before corrected with the CMOS battery.

 

Thanks for the reply, I did try with just 1 stick of ram in various slots, no difference.
Ended up buying a second hand computer with a similar motherboard (only 2 ram slots though) and merging the parts.
A cheapish fix that will keep me going
My concern was that the cpu may be fried too, so buying a new (but outdated lga 1155 mobo) to suit the cpu was risky.
Still wondering how this happened as the surge protected powerstrip appears fine, guess I need a much better one... and a UPS

 

I removed the CMOS battery for 10 minutes or so and replaced it, unfortunately it made no diference

 

Replaced with the same battery? Try a new one.

 

Many powerstrips/surge protectors will only protect for one hit - they're useless afterwards. UPS is definitely the way to go.

CPUs are way more resilient than 'boards

 

may try a different battery, fair call.
I am assuming that the cpu is likely to be okay; just a mild annoyance to test it due to not having a test rig.
powerstrip is still suggesting that it is operating fine, that does not appear to be the truth though...

 

The strip is just acting as a plain extension lead now, no protection any more.

 

With surge protection there is also an issue of the speed of the surge protection activating, ie for a particular SP device how quickly the protection hits in, and we are talking nano-seconds. The better the device, ie the speedier it hits in, which means the fewest nano-seconds it activates, the better the protection.

 

The same pc referred to earlier had the same symptoms at a later date. Disconnected most accessories. Finally reseated the proc fan and the proc itself and cmos battery. Took the ram out. Got a power led on back and a power up indicator on front. Fans on. Put back in one stick ram and cranked all the way. Put in 2nd stick and power but no screen. Swapped ram in first slot. Power but no boot. Bad ram. Similiar to @satrow advice in #3. On that box right now.