I have a dual xeon system with LGA 771 sockets that went dead. I figured, it must be a power supply, so I swapped the ps and I still has no power. I tested both power supplies on another system and it showed the original ps was dead and the replacement was good -- at least the power supply itself energized -- LED on, fan on, cpu heatsink fan on. I ordered another compatible mother board -- an ASUS, vs. the original Super Micro. Same problem with new mother board and 2 new power supplies. When I turn on the ps, the "power led" on the mobo turns on, seemingly indicating power ok to mobo. I connected the power switch, held it dodn, tried reset button, shorted out the switch with a screwdriver, swapped hd's, removed fb dimm. Tried with each of 2 cpu's or both, with fans and without. No matter what I do, the only thing that turns on is the tiny LED on the mobo consistently. Any suggestions? Thanks
So, you had a current draw drag out PS 1 ( fortunately it probably saved the input fuse...haha). I would remove power from every component which you can get by without ( HD, FD, CD,DVD, maybe even case fan.) See what happens when turned on. CPU Fan? Keyboard lights ( immediately ). If you still have no success, you will need to pull the board and hunt for voltage shorts with an ohmmeter. +5 to gnd about 5 ohms, +12 to gnd about 30 ohms etc. At this point, a new board is a good option.
Actually, I replaced the mobo and the power supply and have the same problem. The only other parts to replace are the memory and the cpu's, but I don't see how they can be the problem because I removed them and I still get no power. Shouldn't the power supply at least power up with no cpu and memory?
Is it possible you've left the Bios Jumper in the wrong position. I've done this before and got a no start problem. Man, you got a weird problem, unless your case has a bump in the wrong place shorting out some pins.