No signal input, power button doesn't turn off the computer

[TheBigMass]

I have just purchased a case, and I was changing the motherboard and everything over into the new case, when I finished and tried to power on, the monitor would not come on (has an orange light so it is actually on) if you hold the power button, it will not shut off, you have to flick the psu switch to get it to stop. I have made sure that the video card is pushed in correctly. Checked the RAM, checked the battery, checked the monitor and cables. Tried the holding the power button method. Any ideas?

By psu switch I mean the switch next to the plug where you can turn it off or at the wall socket. You can't turn it off by holding the power button on the front of the case. I checked different RAM, took one RAM out, tested, took the other out and put the other in, and tested. And the video card doesnt need a power connection, it's an nvidia geforce 8400gs. I have connected 2 different monitors to the video port on the integrated graphics, no change at all

 

[jaqie]

re-seat everything. I do mean everything. including the cpu.

 

[TheBigMass]

Reseated the cpu, no change, done hard drive, cd drive etc

 

[Bubbaleone]

There would appear to be a problem with either the front panel power/reset switches or, more likely, you've got the power and reset connectors hooked up wrong on the mobo's front panel header pins. Check your mobo manual and verify which pins are ground, and then be sure the black (ground) wire for the power and reset connectors are correctly oriented.

 

[TheBigMass]

All the pins are in the same place as the manual says. When I push down the power button, the LED lights up for like half a second and goes off, and then when I hold it down to power it off, it does nothing. Also, the HDD LED doesn't do anything and my reset button doesn't work. My usb mouse lights up, however, my keyboard in the 6 pin round connector doesn't do anything, such as I can't turn on caps lock or anything. Could this be a motherboard issue? My monitor still won't get the signal. Everything was fine before I swapped the motherboard etc over to the new case. The only new thing I put in was a new CPU cooler, which supports my motherboard.

 

[Bubbaleone]

Post your hardware specs so we know what you're working with. You may have accidentally shorted the mobo against some part of the new case and the quickest way to determine if that's what has happened is to test it outside the case.

Pull the mobo, place it on a large anti-static bag or a piece of cardboard, hook everything up (including the power and reset connectors from the new case if they're long enough to reach) and then test to see if you still have the same problem. If it'll boot normally then you've got something in the new case that's not fit right. If the case came with stand-offs preinstalled check that they're all in the right location.

 

[TheBigMass]

I've just tested that motherboard outside the case and still does not work, I've also tested and another motherboard.

The one I have been having problems with I have changed CPU and still, won't boot the monitor etc, also, the power LED still does not come on

I have checked a different motherboard which works, and everything is fine, the cables, the cpu that came from the faulty motherboard, everything powers up including the monitor.

Does that help?

Also my hardware specs are:
Asrock G31m-s motherboard
Intel Pentium D 3.0ghz
4gb DDR2 RAM (2x2gb)
450w PSU
Nvidia Geforce 8400GS

It's all old stuff but I bought the case for the start of a new upgrade, was gonna upgrade the CPU and G card etc.

 

[Bubbaleone]

The 8400GS draws a max of 71 watts so the 450W PSU is plenty, but when you tested the components on the other mobo did you use that same 450W PSU? If you ran the same PSU on the other mobo, and all the components worked normally, then it's most likely the old ASRock mobo gone south. If you used a different PSU when you tested the components on the other mobo, and they all ran fine, then I'd suspect the 450W PSU is bad.

 

[TheBigMass]

Used the same PSU in both motherboards. In the one that works I rigged the VGA to the onboard graphics to test everything worked, and it did. Any reason as to why the motherboard stopped working? All I did was move it from a case where everything worked, to a new case in the same day.

Also on the faulty motherboard compared to the one that works, I've realised that the northbridge controller Intel G31 Chipset (heatsink I think it is)? feels a little loose.

 

[denis280]

(heatsink I think it is)? feels a little loose.

you shouls take it off and reaply thermal paste.but that is not the problem right now.as mention before you did reseat everithing did you reseat the ram to.if yes then clear cmos.

 

[TheBigMass]

Reseated everything. How do I clear CMOS? I took out and reseated the battery

 

[denis280]

take the battery out and hold the power button for 30 sec.

 

[TheBigMass]

Done, still nothing. I must have forgot my information when testing earlier. In the faulty motherboard, the cpu I was using, lit the power LED up for half a second and then went off. When I changed the cpu, the power LED sort of flickers but stays on, but still no monitor. I'm baffled lol, both CPUs work in the other motherboard perfectly.

 

[discerning]

Turning off the motherboard by holding down the power button is done via a chip, most likely the Super IO. If it is not turning off after holding down the power button, either the PSU is bad (not supplying enough power to the chip) or the chip itself is bad.