experienced user here with motherboard problem. working on a friend's system and having power issues.
SADLY SUSPECT THAT BOARD OR CPU OR BOTH ARE NOW DEAD.
had spent hours and hours fixing overly loaded and partly functioning Windows XP install with great deal of success (way too many installed programs, many extra startup programs loaded, conflicts with various installs, you name it). went through all hardware and connections as well doing many minor fixes and was just about to return to owner, a friend.
while testing some final adjustments, the entire system shut down. no p/s fan, cpu fan, ho hd spins, no video, nothing. after removing one device after another to get down to only mbd, supply, and switch, still nothing. pulled all power connections, put loaner supply hanging out of case with just ATX power connector to motherboard/cards and front panel switches and powered up. figured it was dead supply (would not have been surprised at this; was pretty sure supply was too wimpy, 350W, for this massive power hungry machine, so got new 500W supply.
both supplies have rear real power switch, btw. kind of important.
get new supply in machine, all plugged in, everything ready. apply power, everything powers on right away from only real power switch. no POST, no video, no beeps (has true mbd speaker, not talking abut sound card), nothing. entirely ignores front panel switch, both reset and power.
removed all connections and devices from chain, no drives, no cards, no kbd/mouse/etc. now only mbd, front panel power sw, and still nothing. rear power switch turns on system (LED on mbd and cpu fan start running) and no front panel switch action. have tried different switch as well, but clearly that isn't really an issue anyway.
currently testing/about to test old and new supplies on bench out of box while only connected to dummy tester drives and powering on by momentarily shorting "power on" (pin 16 on 24 pin connectors, green wire) and ground. will observe voltages and behavior and report back shortly.
don't think specs on the machine are that important in this situation since problem is so generic, but here they are:
ASUS AMD mbd M3A78
AMD quad core cpu 2.3 GHz
1 2G DDR2 RAM DIMM
3 HD (Max 80G, Max 160G, WD 160G)
2 APATI DVD-RW
Promise dual IDE PCI
NVIDIA PCI Express x16 video
ATI tv tuner PCI
Soundblaster PCI (redundant to mbd sound)
many external USB HD (not here, left at other location)
USB and printer port HP printers (also not here)
crazy huge [bleep] case w/ many fans and a couple lights
haven't seen schematics or other specs of mbd to know what this behavior means.
am probably going to swap out motherboards in his box to get it back to him sooner than i may have results on this board.
if possible, please include a CC to me as well as a response here; have "send email from members" turned on in profile.
thanks in advance!