Computer boots up, everything works fine, losses power and motherboard light goes away completely.

Toggle sidebar Toggle sidebar
K

krishadv

Reputable
May 25, 2015
6
0
4,510
I built this system 4 years ago and suddenly one day it started up normally and later it shut down completely. I tried to press the power button on the case and nothing would happen. I opened the case and I saw that the motherboard led was no longer on. I dis-connected and re-connected the power supply cord and everything worked fine for 15 seconds and it lost power again, and does the same all the time.

I have tried the following:
1 - Change to new ram and only one stick.
2 - Reset the CMOS.
3 - Tested the power supply using the paper clip trick.
4 - Removed the GPU and tried again.
5 - Reapplying thermal paste.
6 - Externally mounted the system on a smooth isolated surface.
7 - Removed everything and left only 1 stick of RAM, CPU, Motherboard and PSU.

I have also went through the troubleshooting guide of Tomshardware.com, nothing seems to be working.

PC Configuration:
ASUS P7H55M 1156 Motherboard
i5 760 2.8 Ghz
Cooler Master 650W PSU

Any help would be appreciated.
 
Solution
ko888
Since the motherboard's LED doesn't light up anymore then that means that the PSU's +5Vsb circuit is dead.

Replace with a better quality PSU.
Sort by date Sort by votes
K

krishadv

Reputable
May 25, 2015
6
0
4,510


But after testing the PSU by a paper clip, the PSU was working just fine. Does that indicate that the PSU is not faulty?
Also there is no chance that the CPU is faulty?
 
Upvote 0 Downvote
K

krishadv

Reputable
May 25, 2015
6
0
4,510


It does light up if I disconnect and reconnect the power cord of the PSU.
 
Upvote 0 Downvote
ko888

ko888

Titan
Feb 18, 2009
16,708
41
84,990
The motherboard requires +5Vsb power before it can send the PS_ON signal to the PSU that tells the PSU to turn on its switch mode portion that generates the +3.3V, +5V and +12V outputs.

If your PSU's +5Vsb circuit is faulty then you'll experience the problems you're having.

The paperclip test simulates what the motherboard would do when it sends the PS_ON signal. It doesn't test the PSU's +5Vsb circuit.
 
Upvote 1 Downvote
K

krishadv

Reputable
May 25, 2015
6
0
4,510

Thanks for the explanation, I will test it with a different PSU and report.
 
Upvote 0 Downvote
J

jitpublisher

Splendid
May 16, 2006
8,747
2
31,960


All testing with a paperclip will do is confirm if the PSU will turn off or on. Your PSU can "turn on" just fine, but that does not mean its supplying the correct voltages to the rails. Your PSU can turn on just fine even with a power rail burnt out completely.
 
Upvote 0 Downvote
K

krishadv

Reputable
May 25, 2015
6
0
4,510


I tried with a different PSU today, but it is still not working. I think that the motherboard is faulty, which is the a big problem, because I cant find a 1156 motherboard absolutely anywhere.
 
Upvote 0 Downvote
K

krishadv

Reputable
May 25, 2015
6
0
4,510
The problem was in the PSU. It was just bad luck that both the PSU I tested it on where damaged.
Everything is working fine now, thank you very much everyone.
 
Upvote 0 Downvote
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom