[jmf1775]

I need some help with a very frustratiing problem. Built a computer for my brother in March and it was working fine until last week. He opens an email from FirstWord (Pharmaceutical News) and his screen goes blank with "No Video Signal".

He lives in another state so he's in process of shipping computer back to me as everything we've tried hasn't fixed it. Here's his system:

ECS KN1 Extreme Socket 939 NVIDIA nForce4 Ultra ATX AMD Motherboard
AMD Athlon 64 3500+ ClawHammer Socket 939 Processor
WD Caviar SE WD1600JD 160GB 7200 RPM 8MB Cache Serial ATA150 HD - OEM
MSI NX6600GT-TD128E Geforce 6600GT 128MB PCI Express x16 Video Card
CORSAIR ValueSelect (2 x 512MB) 184-Pin DDR SDRAM Unbuffered 400 PC 3200
AOpen 2-Tone 16X DVD+R 4X DVD+RW 2.4X DVD+R DL 8X DVD-R 4X DVD-RW 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM 2M Cache IDE DVD Burner
NEC Black 1.44MB 3.5" Internal Floppy Drive Model FD1231H-302
Antec Life Style SONATA TruePower 380Watt ATX12V Power Supply
SAMSUNG 710N-BK Black 17" 12ms LCD Monitor 300 cd/m2 600:1 0.264mm Pixel


And here's everything we've tried:

Different monitor w/different cable.
Different video card
Reset CMOS
Took a stick of memory out and tired other stick in deifferent slot - repeated with other stick.

Can't get into BIO's either as same "No Video Signal" appears when starting up. Everything appears to be running fine on inside - fans, ect.

He is running AVG Anti-Virus, AdAware, Spybot, Windows Firewall, and is behind a router and is hard wired.

Finally convinced it was a power supply issue as Sonata case at that time came with 380w PS with only a 20 pin connector and MB has 24 pin. So replaced it with:

New power supply
OCZ ModStream OCZ45012U ATX 450W Power Supply

And...nothing. He's in the process of shipping it back to me and the only thing I can think to do at this point is to take the MB out and place it on a piece of cardboard to see if possibly some sort of short with case was causing ot to start up. If that doesn't work I'm out of ideas other than returning the MB to ECS to have them check and see if it's bad.

Any thoughts on how to proceed or anything else that might be causing this would be greatly appreciated. I won't have computer till Tuesday night so won't be able to try anything until then.

Thanks

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power supply was good call and would have been my call as well...failing that, CPU fried or bad motherboard.

Sometimes, the CPU and motherboard will conduct an electrical current allowing lights and fans to work, but nothing else to happen....this sounds like your case.

Check the motherboard for burned capacitors and if it checks ok, pop the CPU heatsink off and take a look...a bad CPU is almost always noticeable by a black mark....a motherboard may still be bad even though it looks OK

[gerryf]

power supply was good call and would have been my call as well...failing that, CPU fried or bad motherboard.

Sometimes, the CPU and motherboard will conduct an electrical current allowing lights and fans to work, but nothing else to happen....this sounds like your case.

Check the motherboard for burned capacitors and if it checks ok, pop the CPU heatsink off and take a look...a bad CPU is almost always noticeable by a black mark....a motherboard may still be bad even though it looks OK

[jmf1775]

Thanks for the suggestions. The computer arrives tod ay and I'm hopeful we might have found a solution. The problem started about 1 1/2 weeks ago. About two weeks ago he bought an ACER 19" LCD and hooked it up to the system and it worked fine.

Last night he calls me and says his other computer is now starting up and going into a black screen right after post messages. Weird...two computers in one week with similar problem?

He thinks about it for a couple hours and then realizes when he hooked the Acer 19" LCD up to his system he moved the 17" Samsung LCD to this other computer.

Key Point: He didn't swich the cables!

So his Acer 19" was hooked up with Samsung cables and the 17" was using the Acer cables. He switched the cables and presto the other computer immediately boots up without a black screen.

Here's the good part...I have the exact same Acer monitor so when his computer arrives I can hook it up using the correct cables and see if it works. I'm keeping my fingers crossed.

If it does then there are two learning points:

1. With LCD's use the cables that come with it.
2. When troubleshooting hook up a CRT monitor, not another LCD as we did in this case since.

I'll post again in late PM when I have tried this.

[jmf1775]

And the problem was...Bad CPU. Tried the monitor thing and didn't work. Tried to see if I could get a different HD to boot up and nothing. So, finally decided to swap CPU's using my Athlon 6400. His didn't boot up in mine but mine did in his so it was a bad CPU. AMD seems pretty easy to deal with as got an RMA and they said they would replace it. It was a retail version and only 4 months old.

Almost had one disaster when I pulled the heat sink and fan off of my CPU the CPU came with it! And yes, the little lever was still in the down position. After cleaning off the thermal paste I went to reseat the cpu and it wouldn't go in. My worst fear - I had bent a couple pins when it came off with heatsink. With very careful moves I was able to straighten them and get it to fit. Running fine now.

Any thoughts on why the CPU would crash after 4 months of running fine?