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Damaged Power Supply - Damaged Motherboard?

Last response: in Components
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February 7, 2009 7:24:15 AM

Hi guys

I recently made the stupid mistake of switching my PSU to 115V using the switch on the outside, which led to sparks and smoke in the PSU, not to mention me crapping my pants. When this happened I immediately turned the power point off.

I then proceeded to replace the now-dead PSU with a newer 350W one. After installing the PSU and all parts and cables, the system booted successfully, but I was met with an error at the first boot screen saying "NTLDR is missing". I read up on the internet that this was a problem with the hard drive boot order so checked the BIOS, but everything looked ok. Just to be sure, I reset the BIOS to the factory default settings, saved, and exited the BIOS. I also put the Windows XP CD in the DVD drive hoping to get to the repair screen, but the next time that I went to start the computer it would not boot. The monitor was plugged in but remained in standby, and although the power, floppy and HDD access indicator lights were working and the CPU fan was spinning, I did not hear any beeping noises (as I did the first time I powered the system on, before entering the BIOS). After a short time the HDD access indicator light goes out, but there continues to be no signal on the monitor.

I tried removing RAM, video cards, HDDs and the floppy, but the computer still doesn't boot. I also tried the original PSU again but this is clearly damaged because the system doesn't turn on.

What the hell is going on? Did damaging my first PSU damage the motherboard directly but only AFTER the computer successfully booted? Did what happened with the first PSU damage the memory which in turn damaged the motherboard after the first successful boot?

The system is a Pentium 4 2.66GHz with 512MB DDR333 RAM, an 80GB HDD, and a GeForce 2 MX400 64MB AGP video card.

Please help if you can!

Thanks

Jason
a b ) Power supply
February 7, 2009 11:44:39 AM

The hardrive may be damaged. Using only the new power supply, take the board out of the case and place on a phonebook, and install just the cpu/heatsink, memory, and video to post again. No drives connected. If the board still won't post and you have a socket 775 p4, I would replace the board and memory. Fry's.com has 2x2gb of crucial pc6400 for $39.99 with free shipping and a $20 rebate. The ecs G31T-M board is only $34.99 after rebate plus shipping at newegg.com. The e5200 is only $66 for the retail boxed at Ewiz (also called superbiz).
a b ) Power supply
February 7, 2009 12:29:30 PM

If you get "NTLDR is missing", then the system obviously POST, but some info on the hard disk has been wiped out. You don't need to take anything out of your system, but you'll have to fix your Windows installation. Boot from the CDROM and try to repair Windows. If that doesn't work, then reinstall it. Worst case is your hard disk is now defective and you'll have to get a new one.
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February 7, 2009 1:20:04 PM

Ghislang is correct...... If you do not know how to do the repair then just re-install over the old OS and it will save the old stuff to a file... you will be given this option to save the old stuff during the install......
February 12, 2009 2:26:09 AM

Hi guys, thanks for the quick response, but I don't think we have solved my problem...

o1die, I tried what you said and when I powered the system on there was still no signal to the monitor and although the CPU fan was spinning, there was no "beep" at startup.

ghislaing and shabaa, thanks, but the when I boot the system the monitor remains in standby and there is no "beep" so I'm guessing this means its not POSTing?

The main thing is, when I first booted the system with the new power supply IT WORKED for a couple of boots (this is when I got the NTLDR error), but after I went through the BIOS (I think I reset to factory default settings) and put in the Windows XP CD then rebooted, no signal was being sent to the monitor and here I am!

I have included a photo of how I have tried powering on the system with only memory and video installed. If I have left out a cable somewhere or something please let me know!



Please anyone if you have any ideas or if you know that my motherboard is definitely dead (which would be weird because it worked a couple of times before this happened), PLEASE help me!

TIA

Jason
!