Power supply is good, fans running - no display on

It seem that changing the mother board was needed to confirm as there seems to be a problem related to non communication of the mother board with the CPU, RAM and sections.
Swap and confirm.

"i can find my dmm?" did you mean CAN'T?
"its clearly off", what is off?
the fans are 3 pins,2 are power, one is RPM tachometer.
"it all works fine", so you can boot and run any OS, ?

"the voltage reads +12vdc", where, at fan or PSU?
the fans run off 12vdc, they are DC motors (from outside fan)
if the fan runs slow at 12vdc the the fan is bad or is a low RPM
fan, as some are, bigger fans run slow, for less noise.!

first is the CPU fan it must run full speed, if not the CPU will overheat in seconds and ALL CPU shut them selves (by there selves) this way. so CPU fan is first. what does it do... there....?

then BIOS screens. GOT BIOS UP? and running? with, ESC key pressed>.
let me guess your symptoms
1: PC dead. will not boot.
2: BIOS dead.
3: all fans DEAD,.
4: power switch works and all PSU voltages read right, (seems not)/?
5: if the PSU power wire reads right(DMM), matching the side sticker voltages, and the CPU is dead, the MOBO is dead, or CPU is toasted.


here is a modern PSU, sticker.
see 5 to 10 power lines, see them. all must read correctly
if a fan is dead, then its dead if 12vdc is present on the fan power pins.

Remove/disconnect everything (Ram, Cables, Power Supply, Battery, Processor, Pci cards, Display cards if there's one, etc.) from the motherboard, and after while, reconnect/put them on the motherboard again. Make sure you correctly installed the Ram and it's working. Also don't forget to connect both the power supply cables (20 pins connector and 4 pins connector) to the board. Now reboot your system, can you hear anything (beeps)? If this doesn't help, your nearest culprit to the problem is Display card. Good luck

Disconnect everything from the motherboard except the power supply, CPU and power switch.

Turn on the computer. You should hear 3 beeps because you removed the memory.

If you don't hear any beeps, check the power supply. Check all the connections. Did you connect the 4 pin power? Did you skimp on it? A common mistake is to get a cheap, high-power supply. Just because the box says it's 1000 WATTs doesn't mean that will carry a steady load.

Still nothing...

It's either a bad motherboard or processor. If you have another processor that is supported on that board and you know it works, try it. If it boots return your CPU for a good one.

Unfortunatly, if it doesn't boot with a known-good processor that just proves the board is bad; it doesn't prove your CPU is good. You may have more issues.

Try a different CPU. and also try a completely different set of know good memory. If after this the system still doesn't boot up then then the motherboard they installed in defective and if that the case? Get your money back.

Disconnect the hard drives, cd/dvd drives and any expansion boards you have plugged into the mainboard. We want to remove as much as possible to see if we can eliminate the problem.Using the onboard video, start it up again, and see if it comes up. If it does, then its one of the items you disconnected. Power down and reattach one of the disconnected items and power up again. Did it come up? Keep in mind that we want to see the bios start up screen. Once you have attached all the items you will have found the bad component. Replace it. But lets say you didn't get a good system when you disconnected everything. Well, that narrows down the suspected bad items to: the mainboard, the power supply, the memory, or the cpu. The power supply has many voltages coming out of it, keep in mind that the drives, cd/dvd rom drives and fans use 12 volts for spin up. There are 3 other voltages used by the mainboard. I would replace the power supply next with a known good one. Then it gets a little costlier, the memory, then the cpu and then the mainboard. Stick with it. You'll find out which it is. Good Luck.

It is more than likely that when your old power supply died a death, it damaged some components on the motherboard. Replace the Motherboard and chip, and you should be back in business. You can pick up some good value bundles to save money on buying the parts seperately. The power supply working again after turning off and on, is because there is a little trip in the power supply that triggers when it detects a fault. Powering down resets that trip allowing it to try and work again.

no run sistem? well if you talking about OS.or nothing display on monitor but the cpu work, check the conecction between monitor and parallel conector on cpu, video card,cpu fan. power supply.
those are critical parts.

Have you upgraded the memory?

how to fixed your motherboard no display and no beep, 1st you must clean your memory using eraser and brush for painting if not display again try to clean your video card if have a video card using again the eraser and painting brush if not display again try to pull out the bass in the cdrom and floppy disk. if not display you must replace the memory and video card., if not display try to change your motherboard. The beep put speaker in the motherboard.. gudluck guys