computer won't start

**iamtheblues** · 09 November 2007, 03:08 PM

I wonder if anyone can tell me what the solution to this might be. I appeciate that it's a physical problem rather than a virtual one relating to software, but I wanted to see if there was an alternative to replacing everything between the on/off switch, and the socket with the pins attached to the mainboard.
When turning off Windows it will not boot up again. When restarting Windows, it does (used to) reboot. I think the problem is the cable between the on/off switch and the mainboard. After the the last time I switched Windows off completely, it will not restart.
I think, but I'm not sure, that the black white cable marked POWER SW is the faulty one. Jiggling it's position on the pins on the mainboard would occasionally do the trick, but it seem to have failed completely now.
The fans still work when the power cable is connected to the electricity supply.
I think that the power light on the front used to glow steadily, but now it flickers rapidly.
Any suggestions appreciated.
The attached diagram was made with Xara, and was intended for the man in the local computer shop, hence the spanish. But once the pc enters his shop, he becomes costive about letting it back out again. So I'm reluctant to let him have it. Last time it was nearly 8 weeks.
Saludos,
Bob.

**parahandy** · 09 November 2007, 03:54 PM

Could be anything Bob do you have a multimeter and if you have do you know how to use it? you could do a continuity test on the switch and associated wiring, do this with the mains plug removed this will tell you if there is an intermittent or open circuit. The fact that the cooling fan is working suggests power is getting to it but without knowing your computer layout I cannot go any further than that.

**molucca** · 09 November 2007, 04:16 PM

I had a Sony and it got to a condition where it might start if I rolled the case on its side. I took it in for service several times, and it always started. Then the massive power surge, and the hard drive started making noise. My wife has an AN, and could not tolerate the noise. She shut it down before I could archive files while it was still running. Never started again. I am still reinstalling software. Hopefully your hard drive is fine. We tried to install an new motherboard and CPU, but it still had problems. Something touching somewhere. Then the video display wouldn't work if the case was stood upright. We added another hard drive, and tech left the old one installed. Intollerable noise again, and he shifted everything to the new drive, sort of. All my applications were off on a separate partition no longer associated with the system. My system sort of runs, but very slow since the CPU is slower, and the MB doesn't hold myuch RAM.

They are not built to be fixed as far as I can tell.

Rich

**ss-kalm** · 09 November 2007, 04:41 PM

I tend to side with Rich, not sure of the PC cost in Spain, but in Canada at $100+ per hour to have them looked at, it's more cost effective just to salvage ram and drives etc., make the rest into a boat anchor and buy a new one. 3GHz units with Vista installed can go as low as $399.

**iamtheblues** · 09 November 2007, 05:40 PM

Norman, thanks for your reply, I had a look on Wikipedia for "multimeter"
and now I know what it is and does, I think you are possibly on the right track, for I believe the problem lies in the power supply side of things.

Rich, yours is a horror story come to life. It's almost apochryphal, it seems to happen to everyone at one time or another to anyone who has ever owned a computer.

Keith, I'm, inclined to think that the hard drive is fine, no weird noises, and the last time the pc loaded all was well. The drive is new, only installed in the pc under a week ago. Of course, things do go horribly wrong, even in that short space of time, but I think it might be worth having an attempt at a repair. Costs for that sort of thing here work out at about one tenth of those in your part of the world.
Saludos,
Bob.

**Shaman** · 09 November 2007, 06:29 PM

Hi Bob:
Sorry to hear about your problem. It does most likely a power supply-related problem. I've replaced a computer power supply and noticed that the cables themselves were'nt meant to be replaced (at least easily).
The power supply itself is a relatively easy fix, it took me 1.5 hours the first time, working slowly, It may also be that whatever the cables hook into is loose. You could end up with a good power supply and the same problem.
In your place I would look at how old the computer is, the cost last time for repairs as well as having a computer out of service for weeks. I would also look at my budget and the cost of the kind of computer I would want, either in the stores or on-line.
Then if you do replace it, you probably could use the hard drive in another computer. Memory (RAM) is trickier, the manufacturers seem to be almost constantly changing that. If it's a few years old, it's probably either the wrong type or too few MBs to help. The alternative would be to use it as an experiment in working on computers, see how the memory goes in to the sockets. If you want, power supplies don't seem too expensive and you could try buying and replacing the supply in that computer. Make sure it's off and unplugged from the wall. Lay the tower on it's side, remove the side panel, the power supply should be near the top (when it was standing up) Leaving the cables plugging into their places, remove the screws holding the power supply in, first. Still leaving the power supply cables attached, take the old supply out of the case, and trying not to stretch the still-attached cables, set the power supply outside the tower. Then take your new power supply and using the screws from the old supply, attach the new power supply to the case. Then one-by-one, replace the old power supply cables with the corresponding cables from the new supply until all the new supply cables are attached and the old power supply is completely unhooked. Then close up the tower, set it upright, plug a monitor into it, plug it in. turn it on and see if it works.
Whatever you decide, hope it goes well.
Scott

**ss-kalm** · 09 November 2007, 06:30 PM

Bob,

Ok - assuming your going the repair route, I offer the following observations:

The fan is in the power supply so the lead from the switch to the power supply must be ok. The power supply leads could be faulty, but before switching out the power supply, I would check the following:

The leads from the power supply to the main board may be suspect - typically in Canada they are in 2 banks of 10 or one bank of 20 - unplug these (remember how they came off - if in 2 blocks, typically the black wires together in the centre (if I remember rightly) - sometimes these can be refitted reversed which is not a good plan) and check that all the cables are firmly fixed into the blocks and the power supply by lightly tugging. Obviously if there is a loose one that is likely be the culprit.

If the leads are all firmly fixed check the connector thats directly soldered to the motherboard - there should be no play - if there is, it will need resoldering to the board - NOTE: THIS IS NOT A JOB FOR AN AMATEUR ELECTRICIAN WITH A WELLER.

If all seems well plug the connector blocks back in and make sure they are reseated firmly. Again there should be no play.

If at this point if there is still no life, I would suspect either the board or the power supply is faulty - Seek the advise of a professional.

Not sure if you have played inside the PC box before, be cautious. Things are not as fragile as you have been lead to believe, but try not to actually damage anything.

In my humble opinion I don't think you can do any more damage taking a look, and may even save yourself time and expense.

**Soquili** · 09 November 2007, 06:33 PM

Bob the problem does sound like it is the power supply. Much less expensive to replace the power supply than the computer.

Computers use what is known as a switching power supply. The switching is done by a pair of transistors. If one transistor fails the switching action fails. There are portions of the power supply that do not depend on the switching action. The fans are powered by the power from that part of the supply. The mother board depends on the power from the switching circuits in the power supply.

**Mike Bailey** · 09 November 2007, 06:34 PM

I had a similar problem once, intermittent crashes and such, was simply a loosened screw that grounded the mother board to the chassis.

**steve.ledger** · 09 November 2007, 08:25 PM

Please check the ATX switch as it's a very common problem. The ATX Power switch get's a lot of punishment as well as dust, finger grease, cat hair etc and can commonly fail, stick or not work at all. This is part of the group of panel (facia) cables that are fitted to the case which more often than not are very cheap and nasty. The good news is it is cheap to replace. There can be difficulties in removing the case facia to actually physically replace the cable and switch, but this is dependent on what you actually have (some are easy some are a pig)
http://us.st11.yimg.com/us.st.yimg.c..._1971_73640521
http://www.directron.com/atxswitch.html