ASUS M4A88T-M LE & Cooler Master 500W

[lrogers287]

Hello
So I am struggling with either a design flaw or a two bad PSU's or Mobo's.
I am following the troubleshooting tips and am breadboarding this out of the case - Mobo, CPU & PSU only. Maybe I am missing something else.

I have confirmed CPU & CPU Fan in a seperate PC.

In all three configurations - PSU1/Mobo1, PSU2/Mobo1, PSU2/Mobo2 - I get no fans spinning in either the PSU nor CPU fan. Mobo power LED is on.
No system beeps either.

When I disconnect the 20 pin harness and leave the 4 pin in the 24 pin connector, and then jumper the PSU Good signal on the 20 pin harness, both fans come on.

I find it difficult to believe I have gotten two bad Mobo's with the same failure mode. Many people on the egg have very positive experiences with both the PSU & Mobo.

I get the same symptoms with a memory stick and graphics card installed.

Here is my questions.
1. I am considering measuring the resistance between the PSU good and ground on the backside of the mobo where the connector pins come through. SHould I see continuity always or is that a switched circuit from some other part of the mobo
2. If all else fails would you try a different PSU vendor or Mobo Vendor? My preference is PSU as its cheaper .
3. Any other suggestions / checks gladly welcome.

Target system.

Mobo - M4A88T-M LE
CPU - AMD Phenom II X4 945 Deneb 3.0GHz Socket AM3 95W Quad-Core Desktop Processor HDX945WFGMBOX
Cooler - Stock cooler with artic silver paste
PSU - COOLER MASTER eXtreme Power Plus RS500-PCARD3-US 500W ATX12V v2.3 Power Supply

 

[boiler1990]

Do you have the 4 or 8 pin CPU connector plugged in? Standoffs installed? Sounds like you know what you're doing - just want to double check just in case.

It seems unlikely that you'd get two bad PSUs and two mad mobos. Possible, but unlikely.

 

[lrogers287]

In doing a few final checks, I decided to plug in the power switch to the pins on the Mobo. It solved the problem. I have asked the moderator to add that check into the troubleshooting guide, obvious as it may seem.

 

[lrogers287]

Best answer selected by lrogers287.

 

[boiler1990]

Yeah that 4/8 pin CPU connector is important, and the computer won't boot without it. I think it may be in one of the guides already, but I'm not sure.