Something I can't understand...

[DanF]

A client phoned that her PC was not switching on. I went on site to check the system and found that it was switching on and off instantly.

First thing I did was to disconnect the UPS and connect it directly to the wall. It worked. So I've changed the UPS to another one and bang... back to square one. So... it's not the UPS.

Checked the PSU on site by using the usual PSU tester. Everything looked fine as far as I know. So I've started disconnecting the cables, after I've checked that all the necessary cables are connected properly. First one was a molex connector which was powering the only HDD. Powered the system on and it worked, obviously without an OS. So I thought of changing the Molex connector (maybe it's faulty). And it booted fine. I thought, oh well, it was a faulty molex connector (never encountered such thing before). Switched the system on and off several times just to make sure it's fine, and told her that it looks like that was the problem. Told her I will phone the day after to make sure everything is fine.

Today she phoned back, before I did, and told me that it's doing the same thing. Went back to her and asked her if I could take it with me for better analysis. She agreed, I took the system with me, plugged everything in and switched it on. It was fine, until I noticed a BIOS message which said that Overclocking settings are wrong (or something similar). This message never appeared the day before, so I went into the BIOS and set everything to default, re-arranged boot settings and re-booted. Till now everything is working fine.

Was I can't understand is how all of a sudden I get that message. All I know is that the system worked twice the day before, but I doubt the children touched anything from the BIOS. Another thing is that the system is not switching itself off when it's running. It's when it's switched on the first time... and not every time. Temperatures are fine, although I can't see how they can cause such a problem.

 

[Howellga]

I've seen bios' reconfigure themselves if the system lost power during post. To test this theory pull power when system is in post. Might want to change out battery on motherboard for good measure.

 

[DanF]

I will. I'm sure she told me they've been using it for approximately 5 years with no major problems.

But as far as I know a bad battery can't cause the system to switch off instantly right? Well... unless it cause BIOS settings to change when it feels like it. lol

 

[DanF]

Did the same thing. Though I'd do another test using the Power Supply tester.

The 3.3V keeps flashing and changing to 3.6, 3.4, 3.5 and 3.3. The testers keeps beeping every two seconds.

EDIT: To check this, as I wasn't sure, I've plugged the tester in a brand new PSU. The 3.3V remained 3.3V and there were no beeps at all. So I've concluded that there's something wrong with the PSUs 3.3v rail. I love it when I learn new things

 

[TheTechWizards]

Is it a Dell GX270

 

[NYJimbo]

I was trying to put a video card in a desktop a couple months ago and when I hooked it to one monitor the machine would boot up with that "overclocking" message. Only if that card was put into that machine and then cold booted using a specific monitor. Still dont know what that was about but it could have been something to do with voltages or a short or something.

 

[DanF]

Nah. lol

It's not a habit for home users to buy HPs, Dells and other similar computer systems. They'd rather get a pre-built system from a large store. So much so I've never worked on a Dell (should I thank God?)

Is it a Dell GX270

 

[DanF]

Strange things happen sometimes. These computers today...

I was trying to put a video card in a desktop a couple months ago and when I hooked it to one monitor the machine would boot up with that "overclocking" message. Only if that card was put into that machine and then cold booted using a specific monitor. Still dont know what that was about but it could have been something to do with voltages or a short or something.

 

[TekSiDoT]

I've had this problem several times (3 afair) for no obvious reason with my personal machine. It usually happens after not having been switched on for a longer period (which would point to the CMOS battery. Checked that, it's not the battery.)

Also tried the obvious stuff like checking/replacing PSU, removing alle devices/cards and so on.

As it's not a major problem in my eyes and reconfiguring the BIOS takes a minute or less I haven't bothered putting more energy into finding the cause.

 

[joydivision]

Nah. lol

It's not a habit for home users to buy HPs, Dells and other similar computer systems. They'd rather get a pre-built system from a large store. So much so I've never worked on a Dell (should I thank God?)

Err it must depend on the country. I live in the UK and nearly every home has a Dell in it. I am trying to think of any of my regular customers that don't own a Dell

 

[DanF]

Is it different in terms of hardware? Is it more difficult to repair a Dell or let's say an HP and other pre-built systems?

These systems are only used by companies, schools and other government corporations. Never seen a home user using a dell.

 

[Oldtechguy]

Dell GX270 Power off issue

The Dell GX 270 motherboard has had a lot of problems with the capacitors. They received a whole bad batch during manufacture. The problem usually is similar to what you have described. Visually check the capacitors for swelling and/or leaking. If they are bad the motherboard will need replacement.

 

[LunchBox]

Aside from the capacitors which I have been go bad on those GX 270/280 it can still be the power supply. You have to remember that the power supply tested can only test if the power supply turns on and give you its reading. It can't tell you how it would function under load.

 

[gazza]

I have had this overclocking message at bios level before on computers that were using Asus motherboards and have definitely not been overclocked. On each occasion the message was caused by a faulty fan on the graphics card that would work intermittently. I replace the cards in both cases and it solved the problem. It's funny the only time I have seen an overclocking message is with Asus motherboards.

 

[studiot]

Just remember that the GX270 has a totally different motherboard from the GX280.

 

[TekSiDoT]

I have had this overclocking message at bios level before on computers that were using Asus motherboards and have definitely not been overclocked. On each occasion the message was caused by a faulty fan on the graphics card that would work intermittently. I replace the cards in both cases and it solved the problem. It's funny the only time I have seen an overclocking message is with Asus motherboards.

That's interesting - I've been using Asus boards for quite some time now (and had that problem from time to time). However, I've been using a passively cooled graphics card.