Is my motherboard dead out of the box?

[Cardiel]

Hi all. 

My PC died in July and I have been trying unsuccessfully to fix it for two months. I have tested the PSU and RAM and they are not the issue. The problem is my motherboard just stopped working. At first I wasn't sure if if was the CPU (Q8200), so I bought a replacement and then an upgrade (Q9300) and neither worked. So I bought a replacement motherboard (IPIB-LB Benicia) which didn't work. Then I bought another copy of the same motherboard, and another after that. None of them show any sign of life (LED light on, fans whirling in reponse to PSU cord being plugged in). So the question is did I buy three dead motherboards or am I just wiring them incorrectly? I mean both the 24 pin and 4 pin power connectors are securely in place. I have also bought a new PSU just to be sure, and the power cord works fine on my other xesktops. I also tried different outlets just to make sure it wasn't an issuethere, including one at Best Buy.

I thought maybe it was a SATA issue, so I replaced those to no a vail. Then I bought a spare two CPUs just to be absolutely certain it was not an issuethere. No dice.

In summary, I have tried four motherboards (counting the original)  six CPUs, two PSUs, two sets of SATA cables and can't even get the fans to spin

[Lil_Boy_Blue]

Hi

Daft idea, but it will only work if/when the front cover ON/OFF and RESET buttons are functioning.

IE: the PSU does need some feedback from the MOBO to Kick off.

[Lil_Boy_Blue]

Hi

https://support.hp.com/us-en/product/hp-pavilion-slimline-s5500-desktop-pc-series/4162194/model/4206...

There are 9? pins out to the case, and a broken wire or corroded switch/button will stop it dead.

[TheOldMan · Accepted solution]

Here is a method that is used by PC techs when a troubled PC will not work.  And since you have all those spare parts, it should be easy to do.  Get a piece of cardboard large enough to cover a table or workbench.  Lay out the motherboard, power supply, etc.  Connect the motherboard to the power supply, install the RAM and CPU.  Connect the monitor, keyboard and mouse.  Simulate the push button "on" or connect the front leads for the case and see if it starts.

Here is the pinout showing where the power push button connects (pins 6 and 8 )  monetarily connect 6 to 8 and it should start

[Cardiel]

I had considered manually jump starting it, or at least trying to, but couldn't work out which pins were which. I will give that a shot and see how it goes.

Should I assume the board is dead if I can't jump start it? I feel like I have some sort of civic responsibility to report the eBay vendors selling dead mobos but am very reluctant to do so if it turns out I am just missing something obvious.

[Cardiel]

The motherboard on that 5500f model looks very different from the one I have but your point is well taken. The thing is, I don't notice any bent pins on any of the boards. That's what's so frustrating--everything is fine on the surface.

[Lil_Boy_Blue]

Hi

I would try with the reset shorted out, a jumper fitted and momentarily connect the power.

If that did not work I would try variations on those 2 pairs of pins.

[TheOldMan]

The link that @Lil_Boy_Blue  posted for the unit was not for your PC.  Here is the one for the Pavilion p6140f

https://support.hp.com/us-en/product/hp-pavilion-p6100-desktop-pc-series/3942799/model/3975007/docum...

If you scroll down to the motherboard layout category, the picture posted should be similar to the one that PC came with.

The F.Panel pinout is located by itself and by the SATA ports.  The pin that is missing, top of the pinout block, would indicate the orientation.  The two pins on the same side as the missing pin and directly next in line are the two to momentarily short to cause a start when everything is ready. (pins 6 and 8), as illustrated in my other post.

[Lil_Boy_Blue]

Very true.

I found the correct MoBo and counted the 9 pins and posted the wrong link.

Egg on me face.

[Cardiel]

That manual jump start with a screwdriver worked like a charm. I used my new PSU and my breadboarded mobo/cpu booted with no problems. I tried doing the same with my old PSU (still in the case) and could not get it jump started. From this, I deduced that my old PSU was the weak link and replaced it with the newer one I'd been breadboarding with. Now my PC is up and running better than ever. What a relief.

Thanks for all of the advice, friends!