Question can a psu fry a mb? bought used mb pc not booting

[robn44]

bought a 1000w psu. guy wrote it was tested. asked him at the sale. said works perfect and contact if any issue so I felt more relieved

connected it up. not booting. nothing on screen except the monitor saying no signal. reconnected my old psu 750w 4 month old psu. worked just fine

swapped 2 other gpu. 3 total. checked with 2 other psu. meaning my 1 750w, 1 600w and 1 550w. not booting

I have 3 front fans and 1 exhaust fan. using an adapter all 4 are connected on sys 4 pin connectorr on mb. till now when I booted, front 3 spun up immediately and rear exhaust took a moment then spun up.

with the used psu, the rear fan would try to spin but doesnt.

took psu out, let it sit overnight. took out bios battery too. tried this morning. the same. I changed the display port connector trying the other 3.

amd 5600x in there. I have a 5950x I just bought. with using my 4 month old new and good working psu can there be damage to the cpu if I use that to se if the 5600x is fried? maybe motherboard is fried?

what else can I try. thanks in advance for any insight. I bought the psu to have for the 5950x pc im building with 4090

5600x
2x16gb ram
1070
b550m aorus elite

 

[robn44]

ok, so taking it to someone who will test it on the spot. so update

I have 1 pc i7 6700
rx590
2x8gn
has an antec 550w

other pc ryzen 5600x
2x16gb
gtx 1070
sama 750w psu

I thought perhaps gpu was the issue. put 1070 in i7 pc and used both of MY psu and they post. I tried the rx590 in the victim pc and it doesnt post. I dont dare use the used pc I bought in the i7 pc with it might ruining it as well.

so im honing it down to either cpu/mb or ram. im taking ram out from r5600x pc and will use in i7 pc and see if it posts/boots

then ill know if its mb/cpu

one other question. with my tested and shown to be good 1070 750w psu can I insert and try with a new 5950x ?

if the mb is bad can more harm come to anoter cpu I insert or best not to chance it?

 

[robn44]

ok, we know of the $20 psu testers. itsa rectangle and you connect the various connectors in. I had one of those. and it seems all was made at the same factory. they are not reliable at all. It showed a defective psu as good. and here, im sure the psu is bad and shows it as good. my mb will argue its not good.

just came back from a store that said it shows as good but could be some pin is causing some issue. those psu testers are garbage. I snapped mine in half and threw it out. they are unreliable.

if you goto amazon and search psu testers, youll see endless testers. they all look the same and unreliable.

 

[mindless1]

A little PSU tester that doesn't put sufficient load on the PSU to match or exceed the system requirements, even then not being able to test response time for relevant rails subject to fast load increase (12V rail mostly, from video card and CPU), so it can only fail a PSU, can NOT prove it viable for proper system operation.

Being able to fail the PSU makes them better than nothing so I wouldn't have destroyed it, since that is a first quick test to do and you can quit testing if it already fails at that.

If the PSU isn't under warranty, one of the first things I do after measuring voltage is to pop it open and look for vented capacitors or a burnt smell (transistor or diode fried), but I wouldn't do that with the one you just bought.

I can't recommend what to try and guarantee it's safe without already knowing what failed. I would just return the used 1000W PSU, would not risk a used PSU in a high cost system with a 4090 and 5950x.