Cause of No Start

[JJDetroit]

Although I retired a few months ago, I still occasionally respond to problems at a couple of my old department's sites, when the problem doesn't sound like something the service contractor can handle at a reasonable cost. I had a call a couple weeks ago about a Compaq Presario mid-tower, that was throwing up a "No Video Signal" message on startup. Went to the site, and it appeared that the onboard video had died. Took the PC home, to verify that and to try a new video card in the PC.

Didn't have a chance to work on the PC for a few days, and then when I did, it fired right up and ran flawlessly. Called the site back and told them the problem had to be with the monitor, and for them to get another one. They called this morning and said they had gotten one, so I drove the PC back over. Set it up, but when I turned it on, it wouldn't even complete the POST test. Power light on, fans running, but no HDD activity as far as I can tell. Checked to make sure nothing had jiggled loose on the ride.

This has me stumped. Any ideas about the cause of this condition gratefully accepted [img]/forums/images/smilies/sad.gif[/img]

[bigaldoc]

I readily admit that I'm a trial-and-error guy when it comes to hardware diagnostics, but although this could be a blown motherboard, it sounds like a weak or failed power supply to me. You said it wouldn't COMPLETE the POST - did it even start the POST at all, or did it just sit there doing nothing? I guess if either of my swags is correct, the PS is the lesser of two evils and easier to try to replace. Does the company have any "spare parts" on hand from which you could try a PS switch?

[Liberty Raynes]

Hi,
Just a thought. BigAlDoc's suggestion of a blown power supply (or one that's failing) sounds correct, but it could also be other things that mimic the failed PSU problem. I once had a machine that wouldn't boot at all until I jiggled the yellow wire on the molex connector to the boot drive. Fans ran, CPU fan ran, but wouldn't boot. Wasn't even seeing the POST screen, but once I jiggled that one wire, it worked flawlessly, and booted into the operating system. Your problem might be caused by something similar; try swapping power leads to your hard drive(s), and, temporarily, disconnecting your CD-ROM. You also might want to try booting with just one stick of RAM in the machine to see if that's affecting the situation. Again, a failing PSU can mimic lots of other problems, but don't just jump to the conclusion that the PSU is the problem. It could well be something else. Investigate!

[Jezza]

John

Liberty's answer sounds a good one to start on. This is a common problem with the Dell towers I have at work. The technicians have a habit of building a PC and then transporting them in the backs of vans and then pulling them to site on trolleys. All this banging about causes the various boards and wiring to come loose. I often see them on site opening up the box and re-jigging the various cards and wires. Luckily for us we recycle damaged PC's and use them for spare parts.... a luxury I assume you may not have.

Do a set routine and check the connectors to all the drives as well and also the connector from the drives to the motherboard, the latter is a classic one which we discovered a couple of months back...good luck