Mobo P4M80-M4 [Power problem]

I am installing this new Mobo. The motherboard has 2 ATX Power connectors9 20-PIN AND 4-PIN). If i connect both, I have no power.. If I connect only the 20-pin connector, I do have power, but no POST, NO SCREEN. This mobo has a VGA port. Please note thhat I had the same problem with a mobo PM800-M-2, and I thought that the Mobo was defectiove.


Jerry

 

Well, you win some and you lose some with that approach. On the surface, this indicates your old board was probably OK and we have to assume the new board is also OK. You have three primary areas of focus now - Power Supply, memory and video. Do you have either a PSU tester or a substitute PSU you can try for starters? How about some other memory? How many sticks of memory are you using and what is it? Another video card or are you saying its on-board video?

 

mobo P4M80-M4

I checked the Ps with a DMM tester. Found 12vat BLACK and YELLOW wires,5v at BLACK and RED wires, while the PC is on with only the big connector installed .Then I installed the small connector. No power at all. But I found 12 v between the YELLOW and BLACK wires.The Pc will not power up when I unsert both connectors. i checked my memory(new) on another computer. It is Ok. I have an on board VGA port, so I assume that I have video.

 

How many sticks of memory are you using and what is it?



edit: I think the problem here is with your power supply itself but want to eliminate memory as a cause before we pursue the PSU or a short.