Help with No Power, Please

[Farrar]

I have replaced a power supply for a friend of mine and it seems as this has not solved the problem. I removed the cover from the old power supply and the damage was obvious. There were several transistors blown in half, the fuse was blown, etc. He had simply unplugged the unit before the weather became stormy and upon plugging it back up, he smelled smoke. The unit I replaced the old one with seems to be identical. It is also 250 volts and + 5V, +3.3V, and +12V.

Nothing seems to work except the power indicator light on the front is yellow. CPU fan does not work.

Any help would be greatly appreciated.

Thanks!

Jeff

[flyboy747]

Do you hear the hd spin up or can you eject the cd-rom when you turn the power on? Check to make sure that cables weren't accidentally unplugged, like cpu fan to mobo or power connector.

Also try the new psu on another machine to verify that it works.

[Stanley_Kubrick]

perhaps whatever catastrophic event took out the PSU could have nailed other components...
--pull all cards from system except video
--disconnect all drives
--clear CMOS
Simplify as much as possible and try to get a POST; if you still aren't POST-ing , you should look at mobo, processor, RAM.

[Farrar]

Thanks for the quick reply!

I'll try your suggestions and repost.

Thanks Again!

Jeff

[Akuma]

Do a complete system check. Motherboard, Processor and other cards and memory for points of failure. When mother nature takes a stroll through a system, she usually leaves big tracks.

[Farrar]

I have removed all cards except for video, replaced RAM with some I know is good, and checked all connections. Still, all I have is a yellow light beneath what appears to be a lightning bolt on the front of the case. The reset button on the front appears to be stuck as I cannot press it in so I tried unplugging it from the MB but with no luck. The yellow light is the only sign of life. Can I short across the two wires leading from the ON/OFF switch to see if this is the problem? I would hate to suggest a CPU or MB replacement for a faulty switch.

Continued Thanks!

Jeff

[Matridom]

TRy removing EVERYHTING from the case, MOBO, power supply etc. Set it up on your workbench with some anti static foam below it. Don't bother hooking up your case leads for now. A screwdriver will start the system properly (just make sure you short the right pins.). If you have a port80 card, pop it in and see what it tells ya

[Draggar]

When I used to do support, this was a common issue.
It was caused by 2 things (usually)
If the video card is AGP, pull it out then reseat it, make usre it is in all the way.

Also, make sure the processor is in all the way, esp if its a slot style processor.

9 out of 10 calls that would solve the issue, I just hope you don't have the 10th...

[Ruslan]

Most likely that blown PSU took with him also CPU power converter's controller IC,located on motherboard near CPU (usually it's Intersil HIP60**BCB or similar IC from another IC manufacturer). This IC is responsible for switching on power of motherboard using low-level ("zero") signal "power on" coming to power supply (green wire) through motherboard's connector.
Usually replacing that chip can revive the motherboard, but sometimes (in worst cases)another components (power MOSFETs mostly) also can be gone.

Check power supply outside the case. Short the green wire (refer to sticker on PSU or motherboard's manual - it should be "power on" signal) with any of black wires (it's "ground" and case of PSU). If power supply started as it should be - motherboard is gone.

Check also power on switch coming from motherboard, sometimes bad switch could be reason of motherboard's wont boot.
Good luck!