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Need kind hearted experts. tried almost everything, PC won't boot/no display after adding new case fans

Last response: in Systems
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October 14, 2013 12:35:26 PM

Everything is working, fans spinning, USB mouse on, DVD drive tray working but no display at all even when plugged to mobo's VGA; and the power button works when turning rig on but won't work when pressed to turn it off even when holding for a long time.

The problem started when I decided to add two brand new deep cool 80mm case fans. One intake (side) fan with just the 4pin as power and an exhaust (rear) fan with a 4pin and mini 3pin that you connect to the mobo. I got these fans since I replaced the old GPU (GT 430) with a newer one (GTX 650) taken from my new rig since I got new GPUs (HD 7790xfire). The old rig didn't have any case fans since it didn't really need any. The stock rear case fan gave out sometime a year ago didn't bother replacing it with a new one since it didn't really need it. (side panel left open in an air conditioned room)

When I installed the new case fans (added a 4pin peripherals modular cable to the psu, plugged the two 4pins to the cable's connectors and plugged the mini 3pin of the rear fan to the mobo that says system fan). When I pressed the power button the rig turned on for about half a second then it just shut off. Won't turn back on again when I press the power button. I unplugged the peripheral cable and replaced it with a different one. I used the modular cable for a floppy instead. The one with 2 4pin peripheral connectors and floppy at the end. Everything turned on but it didn't boot. The keyboard lights flashed, my USB mouse is on, all fans are spinning, CPU, GPU, the two new case fans, opened/closed the DVD drive bay. But there was no display. I try to turn it off but the power button won't work! I had to turn it off by using the psu's rear on/off switch.

Worried, I took out the modular cable where the new fans are connected and disconnected it from the psu. Then turned the rig on again and got the same result. Everything is running, CPU fan, GPU fan, mouse is on but still didn't boot no display. And still the power button works when turning it on but won't turn it off even when holding it for a long time! Had to use the psu power switch again.

This is an old rig I built around 2/3 years ago. (GTX 650 was add about 2 weeks ago to replace the GT 430). First year was used for gaming but after that it was mostly been used for watching movies since it's plugged to a TV as it's monitor. I know the parts are old and not top quality but this old rig was really very well taken cared of.

The old setup was just those parts mentioned above. The psu using the main connector and 4pin connector for the MOBO. One modular cable (the sata) for one HDD and one DVD drive. The old GPU gt 430 didn't need a pcie cable. Added the new GTX 650 and plugged a 6pin pcie modular cable. Past two weeks no problems at all

To eliminate the GPU as the problem, I replaced it with the older GPU which I know is guaranteed to work. Still the same result, CPU and GPU fans are spinning, USB mouse is on and no display. And the power button still won't turn it off.
Took out the GPU and connected the tv straight to the mobo. Still same result, CPU fan spins, mouse on, no display button won't turn rig off.

I tried most of what was suggested in this thread but so far no luck.
http://www.tomshardware.co.uk/forum/261145-31-perform-s...

I kept everything bare. (Mobo,1 HDD, 1 DVD drive, no GPU, TV plugged to mobo's VGA) Disconected and reconnected EVERYTHING. Same result, everything on and spinning, no display, power button won't turn rig off.
Did the unplug power cable hold power button thing. Didn't work. Same result.
Reset bios didn't work. Same result.
Didn't do the breadboarding as there's barely anything in the case to be honest.
I stopped turning it on again as I kept having to use the psu switch to turn it off.

I tried to make it as detailed with using less words as possible. Sorry if it's too long.
Really really depressed right now because even though I have a newer rig I love this old rig. My first real purchase as an adult/ great sentimental value. :( 
If anyone kind enough to help me please do. Point stuff out. Suggestions. Anything at all.

Best solution

October 14, 2013 1:30:05 PM

HI
A little clarification please,did the rear case fan come with a molex(4 pin) and a 3 pin motherboard connector and did you plug them both in.
This could be important as the fan would only require one of these to be connected and if the motherboard was throttling back that fan ie slowing it down as the temperature was low it would do this by lowering the voltage and if both connectors were powered then a voltage would be applied to the motherboard in reverse and this could damage the controller circuitry on the motherboard.
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October 14, 2013 1:43:50 PM

makkem said:
HI
A little clarification please,did the rear case fan come with a molex(4 pin) and a 3 pin motherboard connector and did you plug them both in.
This could be important as the fan would only require one of these to be connected and if the motherboard was throttling back that fan ie slowing it down as the temperature was low it would do this by lowering the voltage and if both connectors were powered then a voltage would be applied to the motherboard in reverse and this could damage the controller circuitry on the motherboard.


Oh crap I think I did plug both. Kept connecting stuff automatically out of habit. I think that's what caused it. (Stupid me. I didn't know either must be plugged and not both. The darn thing didn't come with any instructions/manual and I just plugged it where it seemed logical)

I took everything out. All the basic stuff works. CPU fan spinning, mouse and keyboard lights up. but it still won't boot/ no display with tv plugged to the mobo's VGA and the power button work in turning the rig off but won't work in shutting it off.

Did i accidentally kill my board? Or can it still be saved? :( (

(Kinda hard finding an am2/am2+ Board now)
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October 14, 2013 1:47:01 PM

Yeah ,if it has damaged the controller then I am sorry to say that the motherboard is not repairable.
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October 14, 2013 1:49:39 PM

makkem said:
Yeah ,if it has damaged the controller then I am sorry to say that the motherboard is not repairable.


Oh good lord where am I gonna find a new board with this ancient socket. :(  any chance I damaged some other parts?
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