Gigabyte H55M-USB3 Wont start without starting ritual

[Xperience]

Hello to everyone, I have strange problem with my computer:

When I press the power button on front nothing is happening, computer seems to be dead.
I tried with only 1 stick of ram in various slots on mb and shortened front pwr_button pins to be sure that case pw button is ok, still wont turn on.

Then I disconnected psu from the board and shortened green/black wires on 24pin connector-PSU started, I measured voltages and it seems to be all good

After few hours and million attempts to start mb by shorting the pw pins it started with one normal post beep and booted windows.
So I run hw manager and other programs to monitor computer voltages and temperatures, everything seems to be normal..

Then I shut down computer, put all ram memories, connected front power button and it started normally by pressing the button.
I tried to turn it off and on a couple of times and it worked normally, then I turned it off and went to sleep.

Next morning I pressed pw button and nothing happened, I opened the case and reconnected all connectors, computer still wont turn on..
Then I tried reconnecting 24pin connector while PSU switch is on (ON) position and while I was putting connector back all fans and lights and HDD went on for half a second, I tried to press pw button and again nothing..

Then I disconnected 24pin connector and while putting it back I stopped when connector was half way connected and I get lights and fans turning on and off every half a second in a loop

The next thing I did is pressing the power button on the same time when fans and lights come on and forcing 24pin connector all way in.

after few attemps, connecting and disconnecting 24pin connector and pressing pw button in the SAME time it continued to work for a second, turned off for second and started normally by itself, booted windows and all worked normally.

I also tried connecting green/black wires on 24pin connector while its connected to mb and it turn all fans but no boot and no post beep..

So every time I want to start computer I have to pull out 24pin connector, put it half way in and when computer starts to loop I have to press the pw button and force connector all way in in the same moment and it will start.

This don't work from 1st attempt but if I do it couple times I get the right moment and pc starts.. When pc start it work normally and everything is ok until I turn it off and leave it for some time, then sometimes it will start by pressing pw button sometimes not.

If I turn it off and disconnect power cable for few seconds it will not start by pressing pw button but it will start by tricking it with ritual I explained above.

I tried with two other psu , other ram, hdd, reseting bios, adding gpu and it still wont start like it shoud.

Is there anyone who can help me?

My Hardware:
MB: Gigabyte H55M-USB3 v2.0
CPU: Intel Core i5 661
RAM: 2x 4GB Hyperx DDR3
HDD: WD 1TB
PSU: Steg 350w

 

[Cycloid Torus]

60/40 bet that you have a failing PSU. Try another known good (check your amps draw - should be >400 watts with any kind of decent video card). Possible that the Voltage Regulator chips or a capacitor are failing - hard to diagnose - inspect motherboard under strong light and magnification.

I re-read your ritual and I think what you are doing is 'tricking' the 'power good' to think it is 'good'. Also look for bad solder or cracked solder joints.

 

[Xperience]

60/40 bet that you have a failing PSU. Try another known good (check your amps draw - should be >400 watts with any kind of decent video card). Possible that the Voltage Regulator chips or a capacitor are failing - hard to diagnose - inspect motherboard under strong light and magnification.

I re-read your ritual and I think what you are doing is 'tricking' the 'power good' to think it is 'good'. Also look for bad solder or cracked solder joints.

Thanks for answer, I have already inspected board and didn't find any visual damage, will look again..
Tonight I will try with Corsair CX750M PSU and see what is happening.

Is there any way to electrically inspect mobo?

 

[plankton23]

1. Be careful while in your case unplugging and plugging in 24 pin cable while power is connected. Not recommended. You can fry your mobo and/or cpu or both.

2. Agree with CT that your PSU is more then likely the culprit. If switching out PSU for a known good working PSU doesn't work then you have a bad mobo or cpu, more then likely from the way you leave the power on, unconnecting and reconnecting cables.

3. Yes you can test your mobo electrically....you will need a multi-meter and know all the voltages of all the embedded chips PCI ports on the mobo and it's very labor intensive.

From your system specs listed....that is a pretty old (2010) mobo and cpu. I see there's no mention of a GPU. Do you have one installed? I can't find out anything on your PSU, are you sure that's the right make/model?

I would consider upgrading your CPU/Mobo/RAM.

 

[MaikuTech]

Go ahead and buy a new psu if you are having that much of a problem getting it to boot.
Its already on its way to die sure you can jump start it like an old beat up dodge truck.
However it will give out real soon, been down that road many times, usually its best to just chuck it and buy a newer psu.
https://www.amazon.com/dp/B00H33SFJU/?tag=httpwwwtechsp-20

Make sure your case wires are connected to your mobo, you don't need to force it.
Grab the manual for the mobo, look at the diagrams and do exactly what it says to put them.
Lets say you have 'pw" power switch, the letters on the front should be turned around.
While the gold circuits is facing towards bottom of the case.
Try each one carefully and power on the machine, if you get it to come on.
Thats great news, however, shut it back down and do the next one for the next set of connectors.
Even with a shot power supply the case leds on the front will get powered on if connected right.
Don't forget the soda and snacks, sometimes you maybe there for a long time trouble shooting it.