ASUS ROG THOR 1200W PLATINUM PSU

[krsta]

Hi guys, hope someone could direct me in right way.

So i got the ASUS ROG THOR 1200W PLATINUM for 15€.

The first time i plugged it in wall socket there was no 5VSB present, so i disassembled it took a little peak inside and left it on shelf for a day.
Next day the 5VSB was present and the psu worked the whole day (outside of computer, shorting PS_ON to ground).
I tested it for a few days like than and then installed in my computer, it worked flawlessley for 1 month.(gaming and such for a few hours).

Few days ago i left it torrenting and saw that it rebooted 2 times after 2 hours working, after that it works for few minutes(10, 15) and powers off , and now it powers on and then off imediately(i can hear relay click when powering off ).

If anyone has any idea or repaired this PSU i would like to hear it.
I will take it apart and look for broken solder joints (it has small dent on one side maybe it fell or was hit ), take a look with thermal camera.

[sam_sam_sam]

Post some pictures of both sides of the circuit board or boards so we can see what you are dealing with

[krsta]

Hi Sam, thx for replying.

The PSU model is :



I left the PSU in the storage for 5 months or so, took it out and it was working for 3 total days without an issue(without load, shorting PS_on pin).
On the fourth day it started turning off with the relay click sound. The only way i can power it on is pulling the PS_ON pin out then in again (i have tried leaving it in and using power switch to turn on and off but it would not power on).

When it works, it works fine according to PSU tester.

The PS_ON voltage is 2.44V and resistance is OL even on Mohm scale.


I have taken some pictures of the psu ill put them under.


The resistance of green NTC near the large capacitor is 5 Ohm at room temp, is that ok?


This is the small board on the side, i have used a thermal camera to see if anything is getting hot and the SOT ic in the lower right corner is 12V -> 5V ic and it gets to 66 degrees celsius



The 2 SOT23 IC-s on the lower side of the board get to 60 degrees also, the rest is cold.



Now some thermal image photos:
Upper and bottom side.


If you have any idea feel free to share.

[gzc2013]

I had similar problems with two asus thor psu. First had faulty protecting ic weltrend 7527. It had all voltages on the sensing pins. But sometimes it started, sometimes not or shut down with no reason. Second psu had all voltages on the output connectors during startup but it shut down immediately. Main 5V was missing on weltrend ic sensing pin. It was caused by faulty LSP5523 (-12v buck converter).

Good luck!

[krsta]

Thank You very much. I now have a starting point.