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Sometimes it starts sometimes it doesn't...

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11 replies

by afonso.marques

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Hi,
My system has the following components:
- ASUS P5B Deluxe;
- Core 2 Duo E6800;
- Noctua NH-U12-P CPU cooler;
- GSkill 2GB DDR2 800;
- nVidia 8800GTS 320MB;
- 2x Seagate 500GB 7200.12;
- Be Quiet Dark Power Pro 850W;
- AEROCOOL COOLPANEL 2 PRETO fan controller;
- NOX Coolbay 25 chassis;
- 1x 25cm side fan;
- 1x 12cm front fan;

The problem: from time to time it 'remembers' and it just doesn't start at all! Not even the fans!

A couple of times, disconnecting the power plug for a few seconds brought it back to life.

Then, when it doesn't work, I open the chassis, reseat every simgle component and 'voila' - It is alive!!!! Until the next time... :(
By the way, it has already happened 5 or 6 times now.

Help...

11 replies

by ---tk---

almost sounds like your Power Supply is going out... try one component at a time IE: pull the plug (hold the power button in for 5 sec, purge the power) reseat the GFX card... plug it in, and try to power it up. If that doesnt work, pull the plug, purge the power, reseat the memory. And repeat till you find the component that is causing the issue...

by rob miners

is on to something with the PSU. It sounds like it is faulty. Here's a couple of other things to try.

Test the Power Outlet or Power/Board by plugging in a radio or lamp.

Try another Power cord/lead if you have one.

Remove the Power cord from the PSU to discharge the Capacitors in the Power Supply. Then press the Power button for 10 seconds to discharge the Capacitors on the Motherboard. See if it will start. If it does start you can replace the (PSU) Power Supply Unit as it is faulty.

Swap the Reset connector on the Motherboard to the Power connector to rule out a faulty Power switch.

Remove the Power lead from the PSU, disconnect the 20-24 pin power connector from the motherboard. Reinsert the 20-24 pin power connector to the motherboard.

Swap the Power Supply unit for a known working unit if one is accessable.

Check the Capacitors around the CPU for swelling or bulging. They should have a flat head with a cross indent.

Clean the golden edge of each memory stick with a soft rubber/eraser, remembering not to touch the golden edge of the memory stick. Check with one stick at a time, remembering to disconnect the power from the PC.

Remove and clean the Video card with a soft rubber/eraser and then reseat it.

Remove all Add on Cards and see if it will start. Clean the add on cards before reinserting them one at a time and testing.

Faulty Fans, Dust and Grime build up on the Heatsink restricting air flow. I would give the inside of the case a blowout with compressed air. When blowing air through the fans make sure that you physically stop them from spinning, as they may generate power and blow something up. Remembering to ground yourself by placing the back of your hand on the Power Supply Unit and not moving your feet. By not taking this precaution it is possible that you could inadvertantly cause damage to the PC from an electrostatic discharge. Then remove the Heatsink, giving it a thorough clean and reseat the CPU applying new CPU grease. If the Fans spin freely when you give them a spin they are probably OK. If there is resistance replace them.

Edit: LOL ---TK-- not ___TK___

by mjd420nova

I've seen this a few times and have come up with two reasons that took some extensive troubleshooting to nail down. The first fault was in a power supply that was bad. It was one of the type that has a low voltage power switch on the front panel. The othe rfault was a short on the motherboard on the five volt line that stopped the power supply from starting, it was the classic where the fans tried to turn but stopped right away.

by afonso.marques

Hi all and thanks for the suggestions.
I tried all items you said in the previous posts I also tried to assemble all the components outside the box and it just worked ok.
However during this past week it happened again.
I also checked all the fans - they're ok.
Disconnected the fan controller but nothing.
However something 'new' happened. One of the times I disconnected the mains and put it back again the CPU fan rotated for a brief moment, is this normal?
I need serious help, so far PC help... Who knows if this stuff turns to vudu help...
Thanks again.

by oh smeg

Yes it is perfectly normal.

Don't worry about that. It's also not uncommon for the system to start when you plug in a Active Mains Lead. This is all down to the Power Supply Fitted and doesn't in any way imply that it's on it's way out, just shows how that particular PS works. ;)

Col

by afonso.marques

Hi again...
Well, finaly I found out what was going on.
Although I believed that this PSU, which I found a bit expensive at the time (about ?150), would be more than enough for my system, well, it turn out not to be.
I unplugged all the stuff from it, made a short circuit between the Power-On and GND as well as Power-Good and GND (a well-known test) and it was dead.
Now, I'm looking for a substitute for this equipment. Any ideas?
Thanks for everything.

by oh smeg

In one case a Antec PS stopped a 11KV hit killing a computer during a storm that brought a tree down onto the Overhead Power Lines.

The falling tree brought the High Voltage lines into contact with the Mains and feed 11.000 Volts AC into the Mains Distribution Grid. The only thing in the house that was connected at the time that was not totally destroyed was the computer case. Though the Power Supply was Shot completely when I fitted another one the system fired up and ran perfectly for the next 3 years. The down side is that it was the only electrical thing in that house/Neighborhood that survived.

A good Power Supply is supposed to Sacrifice itself to protect the insides of the case. The PS is still a much cheaper unit than replacing the entire system and it is supposed t be in place to filter out a lot of the spikes and other junk that comes in over the mains.

Unfortunately many of the cheaper No Name PS's just are not capable of doing things like that and it is the sign of a good PS when they die and leave the internals of the computer intact.

Corsair are now making PS's and I'm told that they are very good but I have never used one so I can not comment on just how good that they are. I do know the Gigabyte PS's are not that great they are better than the No Name ones available but not that much better. ;)

Col

by afonso.marques

I talked with BeQuiet guys and they told me to send the PSU back to them since it's still within the 3 year warranty time.
In the mean time I'll look for an ANTEC to replace it and once I get the old one back repaird, refurbished or even a new one I'll put it in my new gateway/'backup server' I'm assembling.
Thanks again for everything.

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