Question Mystery PC wont turn on. (Works fine in shop))

JoaoG76

Commendable
May 26, 2020
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1,515
A couple days ago turned off PC as usual and went to sleep. Next day PC wont turn on. Receives power, mouse lights up, mobo has light on so does the GPU. Called tech support and they brought new PSU to run tests. New PSU wont make PC start. Tech support takes my PC to shop, PC working fine there. All sorts of tests done, cmos battery removed and reset, ram, gpu and mobo all tests ok. New PSU and current PSU tested. All fine. Tech makes video of PC running in shop with all my components in. Tech brings my PC to my place, PC wont start. Changed wall plugs, got a current stabilizer and tested new power cables. Pc wont start. Pc goes back to the shop. PC works fine... PC comes back to my place, still doesnt power on with power button or otherwise. Reset cmos by removing cmos battery and turning off PSU and then with no cmos battery and turning on PSU, clicking the mobo power button finally PC comes to life (at my place). Today... Turn PC on.. no activity. Same as before, receives power, mouse lights up, mobo and gpu have power. Tried the same process as before and now doesnt turn on, again. Mystery to me and to my tech support. Can anyone help??

Aorus Gigabyte - GA-AX370 - Gaming 5
Rysen R5 2600x
RAM 2x8gb
GPU Asus RX 580
PSU 550 W
 

Karadjgne

Titan
Ambassador
I doubt it's the pc. I'd lay odds it's the circuit the pc is plugged into. 2 easy tests, plug a hairdryer into that outlet and turn it on high heat. Run an extention cord from the kitchen or bathroom outlet to the pc.

Checking voltage on the outlet usually doesn't help, you can get voltage from a hairline connection because testers are so low amperage draw. But a 1500w hairdryer is anything but low amperage and I'm betting it won't work right.

There's more than likely a very loose/burnt connection somewhere in an outlet between that one and the breaker box, if not at the breaker/neutral bar itself.

You are getting enough voltage/amperage from the wall to turn on the psu, but not enough to power the cpu to start boot process. The shop you took it too doesn't have that issue, so the pc works just fine there.

If the hairdryer doesn't work right, you'll have to manually, physically pull every outlet from the wall that's on that circuit and check for a loose/burnt connection. Could be the black wire just as easy as the white. Might have to get an electrician to check the breaker panel for loose power and neutral wires.
 
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JoaoG76

Commendable
May 26, 2020
13
1
1,515
Hi, took me a while to see what was happening and the plot thickens...
Electrician came by to check installation, nothing appears to be wrong. Switched power cords to computer, extension cord, got a current stabilizer and the new tech guy took the pc with him, and still no fix. Couldnt start it. So he brings the pc back to my place where I plug it in and leave it for the night. Next day I did a few tests like removing cmos battery and turning on an off, or holding buttons for up to 30 sec on the mobo, as recommended on the manual. Nothing worked. Still dead. So I laid down after and lunch and mysteriously the pc comes to life. No buttons pushed for about an hour or 2. There was some difficulties accessing the ssd drive and posting but i guess that was done during the transportation from the day before. After fiddling around with the bios, baby was back. All normal. Working as nothing happened. Happy, later went to bed, put pc on sleep mode, afraid to turn it off again and next morning, wouldnt start again. Same story, power is running through the machine but doesnt turn on. Again the same situation where unexpectedly pc turn back on by itself after 10 min of pushing the power button. Pc is working, all day no issues. Today same problem, last night i turned it off, today wont start, still waiting for it to power up... but I'm getting less hopeful today... What can it be? Mobo? PSU damaged components? I live in a high humidity environment can this be a factor?