Plus Double Check My Troubleshooting

Leonardo

Problem: a friends new build has no video signal

Specs: Asus P5WD2 (Socket 775), PCI-E video, Antec 380W (new), Pentium D930 (yeah, used to be my board and CPU, Kingston 2 X 1GB Hyper X DDR2 800, ATI 2400Pro (PCI-e). The 380W PSU has dual 17amp 12v rails

Fans spin up, power LED comes on, all seems normal except no video signal. I can't tell if the hard drive was initializing or not. It's a very quiet SATA. This computer never made it into BIOS, or was never observed.

Steps taken:

-- substituted known, good RAM
-- tried two other known, good video cards - one PCI-e and one PCI
-- substituted a known, good, PSU with good +12v rails
-- reseated heatsink on CPU (it was a little loose but 75% contact with CPU)
-- removed motherboard, reinstalled
-- CMOS reset
-- battery removal, rest, reinserted

Can you think of anything else? I'm thinking maybe there was static shock somewhere either with me when I removed the board from a system a couple weeks ago or the buyer when he assembled his system.

Ryder

"Substituted known good ram" - 1 stick or 2? Was the CMOS cleared in combination with this step? Test with 1 stick, clearing CMOS before.

They used to be your board and CPU, so CPU has worked in this board before, correct?

Leonardo

No, I did not clear the CMOS in between the RAM swaps. I've never done that before in countless builds and troubleshootings. Hmm, learn something every day. Would faulty RAM prevent a video signal? (not challenging you - like I said, learn something every day)

Oh yes, the processor is good. Both the motherboard and processor came out of the same working system. I mean, I shut the system down right before I disassembled it and packaged the parts. Disassembly was in my garage with me standing on a dry, concrete floor. Parts were cleaned then immediately put in anti-static bags. Frankly, I think the buyer somehow shorted the board and killed a critical circuit.

Another question: will a motherboard even get a power light and spin up the fans if the processor is dead?

EDIT: I substituted two sticks, tried one at a time and together. No Sir, did not reset CMOS in between swaps.

kryyst

Try running it with no video card and no ram in it and see if it beeps at you, then put the ram in, the beeps should be different, then add the video card. No need to reset the CMOS between everything, if you've reset it once that's enough it'll be at the default settings.

Leonardo

Something else I thought of: the computer has one of those SATA cables with an integrated LED, if the hard drive is receiving power, even if the board doesn't boot (doesn't seem to - no video), shouldn't that LED light up? I'm thinking there are more problems here than a bad video signal circuit.

TheLostSwede

It's either the cpu that is not working or something is shorted somewhere.

Rip everything out of the case unless you already tried that. Put the basics on a box or whatever. MB, cpu, hs/fan, ram, videocard and a harddrive.

Leonardo

I essentially did that, except not outside of the case. The grounding in the case was spot on. There were no problems with the case walls, the brass standoffs, the mounting screws, and so forth. But yes, I did tear apart the complete computer and put it back to together piece by piece. I never got more that a power-on LED lighted on the motherboard. Never once got any beep codes at all. I am not positive, but I also don't recall every hearing the hard drive initialize.

An earlier question rephrased: will a motherboard power up at all, or more than just one or two seconds if a CPU is non-functional? I've only had one experience with a dead CPU before. In that case, if I remember correctly, there was no more than a blink of motherboard LED(S) and no fan spinning.

Snarkasm

Just to check in, as useless as it may be, I did just solve a problem with a friend of mine's comp with the same symptom, no video output. His issue was a memory problem; they were in the wrong slots in a dual-channel setup. I know it's almost certainly not your problem as I'm sure you've built enough systems to know your way around that, but I figured I'd throw it out there for others in the future - your memory can indeed prevent your video output.

Leonardo

That's a smart comment. Yes, actually, when I got the computer from him, one of the things wrong with the build was that he had the two RAM modules in positions 1 and 2, instead of 1-3 or 2-4. Correcting that, and running with only one stick at a time made no difference. Installing my own, known good RAM made no difference either. I subsequently tested his RAM in one of my computers and it came out aces.

I've just written this one off. I've given the kit to someone here at Icrontic. If they find either the processor or the motherboard to be good, they'll pay me a nominal amount. Motherboards don't live forever.

But then, it might have been the processor. The CPU heatsink was not mounted firmly when I got the computer. I don't know whether that was due to transporting the computer or whether he didn't install the sink correctly.

Water under the bridge. I will probably hold off on selling any more components on Craigslist unless I stipulate to the buyer it's an 'as-is' sale. But I couldn't do that. Despite the phrase above my avatar, I'm a nice guy.