Computer not starting, tested PSU with paperclip but uncertain about test results

[DragonGunner]

Hi guys!

I had my computer shipped overseas, in parts, and just finished reassembling it. When I try to boot, the GPU lights and the case fans turn on for a sec then off. I read a few other threads that suggested trying the paperclip trick to trick the PSU into thinking the computer is on (to test fan). Only problem was that some of the cables for the PSU (two 2.5" hdds, and the 8pin mobo connector) are in really tight spots that would require disassembling the whole rig to unplug, so I left those in.

The other Sata power cables, the GPU power cable, and the 24 pin ofc were unplugged. When I performed the test (repeatedly) the PSU fan spun up briefly, then nothing. In order to get it to happen again (for sequential test), I needed to unplug and plug the PSU - same result.

What does this mean? Is my PSU (which I don't have a receipt for) fried?

I don't have a spare PSU to plug in, and I'm strapped for cash, so if I replace the PSU and the mobo turns out to be the problem, I'm screwed.

Any ideas or insight? Thanks

specs:
850w seasonic bronze PSU
RX 480 gaming X 8gb vram (which is a power hog and has been troublesome with drawing too much power in the past)
Gigabyte 990FXA-ud3 mobo w/ FX-8350 (not OC)
4 HDDs at 7200 rpm, one 64gb ssd
2x8gb DDR3 RAM
NZXT S340 Elite case with 2 120mm and 2 140mm case fans

 

[geofelt]

The "paper clip" test is essentially worthless.
It can only confirm a dead psu if the test fails.
It does not in any way confirm proper operation if the test passes.

Seasonic is a very good quality psu, and I can see no way it could have been damaged in transit.

Check first to see if all the plugs are secure and ram properly seated.

If such a check gives no joy, you must disassemble the whole thing and test it outside the case.
Start with the minimum of connected parts required to get into the bios.
No peripherals and one stick of ram.
Go from there.

 

[DragonGunner]

The "paper clip" test is essentially worthless.
It can only confirm a dead psu if the test fails.
It does not in any way confirm proper operation if the test passes.

Sure, but can you tell me if it did in fact fail? I'm not clear on whether the fan was supposed to continue running or not - it only spun up for a few moments.

Also, when you say no peripherals does that include the GPU?

 

[geofelt]

If a ram card is not seated properly you would get those symptoms.
It is very doubtful that the psu has failed.

I assume your motherboard has no integrated adapter capability so you would need a graphics card installed to see even the bios.

 

[DragonGunner]

Okay, the PSU is fine. Tested outside the case, it booted without issue. So, where's the problem? I assume this means that there was some sort of short between the mobo and the case? How do I find and fix it?

 

[smorizio]

as the pc was shipped and your having an issues. start thinking the pc as brand new un built pc. pull the mb out of the case. with the mb out of the case if you have a large heat sink and it was on the mb when it was shipped. i seen large air cooler pull cpu chips of of cpu pins before. also check that the cooler has not ripped the cpu chip and cpu assembly off the mb. as we dont known how you packed your parts for shipping. take a few min and use a good led flash light and a magnifier look for missing waved on parts on your mb parts. in shipping if you had more then one part in a bag they may have damaged each other. if you did pack the pc well. if you insured your pc parts. use a local shop see if any part is dead and then put in a claim with the shipper.

 

[geofelt]

Okay, the PSU is fine. Tested outside the case, it booted without issue. So, where's the problem? I assume this means that there was some sort of short between the mobo and the case? How do I find and fix it?

The likely problem was that some connection was jarred loose while in shipment.
Testing outside the case proved that all parts are ok.
All you need to do is to put it all back into the case.

 

[DragonGunner]

So I've located the problem, but it confuses the heck out of me: one of the SATA power cables (which powers my 64gb SSD and a small 500gb HDD I salvaged from a laptop) causes the computer to fail to POST when plugged into the PSU. The cable plugged into the PSU right next to it powers two other, much larger HDDs, and isn't problematic at all, despite what I'm certain must be larger drain. I've tried switching the sockets they're plugged into in the PSU (there are 3 for SATA) to no avail. I'm at a loss as to what to do next, especially because my OS is on the SSD and all my games on the laptop HDD.

 

[DragonGunner]

Update: the issue is with a molex to SATA splitter cable. I presume it's a short circuit. Without that cable, the computer POSTs and boots fine (albeit sans 2 drives)
Thank you all for your help