Can anyone help with a Dell 9100 problem?

[BabyBear]

Hi Guys,

I have a Dell 9100 desktop that, without warning, is not starting. When switched on the switch light shows green, the fan on (what I believe is the graphics card) runs, the green LED on the main board the other components are fitted to is on and there is a peculiar noise (find it hard to described probably a loud buzz) which can be heard for a couple of seconds at a time and will come and go for maybe 15 seconds. The noise seems to be coming from somewhere on the main board which is fiited vertically to the casing. Nothing shows on the monitor, generally the monitor (Dell) power switch changes from amber to green on start up, however it stays amber with the monitor remaining blank.

Thanks in anticipation,

BB

[Loose rivets]

It sounds like the power supply might be either faulty, or being burdened by a fault causing an unwarranted load. Almost always, such a fault would cause the PSU to shut down...maybe this is somehow on the cusp of doing so, and oscillating as a result. Getting rid of everything out of the equation used to be the way forward. Bare board, apart from CPU and memory, and then see if you got the POST check beeps. Nowadays, some of the bits are very expensive and it's a toss-up between not interfering with them or risking them being damaged by spikey power. Tough call.

Do the keyboard light flicker during the attempt to start?

Some time ago I posted on a job I did on my Son's workstation. It was a twin Pentium Pro, with a graphics card that cost more than a car. It was total no-go. The point of this is that it turned out to be the most simple and unlikely culprit. I'd stripped everything out - including the CPUs - before the fault showed itself. I'll try to find the link.

Motto, lots of thinking, and minimal stripping. Though I'd never have guessed at this one.

Did the computer give any sounds on the internal speaker on start up - prior to the fault? If so, does it still do it?

USB devices have a 'hard' 5v supply to them, so try removing any USB device, then any PSII type things like older mouse or even keyboard. They are easy, so it's worth getting them out of the equation.

It sounds daft, but also try disconnecting the speaker if it's an off-board type. You'll see why if I can find the link.

Do you feel confident about removing devices from the board? Sadly, so much stuff is on the MB these days that there is often not much to pull. But disconnecting the power to CD etc., is one step to take before the more serious stuff.

Memory might be reduced to one strip. No go, try the other strip.

If you have to tackle the graphics card, you'll have to look for other clues to whether it's working or not. It would be nice to leave that in till last, so that you can see what's going on, but you should be able to tell if the system comes back to normal just by the sounds of speaker/hard-disk/other fans etc. The hard-drive warning light flicker should be a rough indicator of normal booting.

That's enough for the moment, let us know how you get on.

Here it is, different, but shows the pitfalls. The bit about nuts and bolts in the works, is as true today, as it was in Marconi's time.


http://www.pprune.org/computer-inter...ml#post1805980

[BabyBear]

Thanks for your time LR,

I am happy to give it a go, can't stand the thought of paying a fortune for an engineer to relpace something simple.

I have removed the graphics card, wireless card and network card and still get the same noise.

I have been searching the web and trying to follow a Dell diagnostic procedure (not easy), which is indicating a USB issue? The machine was dismantled for decorating and I can't be sure the USBs were replaced in the same ports (there are only the mouse, keyboard and a dongle). It seems the cure is to remove all USB devices and reset the BIOS. I also found reference to a possible problem with the actual memory, but not convinced on that one. I am currently trying to establish how to reset the BIOS and what it means?

Thanks for the link.

Cheers,

BB

[Avtrician]

Is the noise a grating type of thing. It could be the cpu fan or the hard drive. disconnect the power lead from the hard drive and try a restart, if no noise then there is the problem.

You dont mention if you have any display on your monitor, if you do, that should give an indication of where its hanging up.

The USB devices dont realy care where they are plugged in. If no display, check the monitor connection, and check for bent pins first (common problem).

If no joy , try source a video card to eliminate that problem. (If pc senses no video out, it wont start usually).

I will think of more to try on next posting.

[twiggs]

Originally Posted by BabyBear

I am currently trying to establish how to reset the BIOS and what it means?

There is usually a couple of ways to reset the bios, but the easiest is to remove the battery from the motherboard and replace it after 10 seconds.
There is no harm in trying this especially as the support website has suggested it.
Doing so will just reverts the bios to default settings.

[Keef]

Normally if there's a problem at startup, the POST will beep its codes to tell you what's up. If it doesn't do that, the problem is very early in the boot sequence. Certainly, the BIOS isn't likely to be the problem (and you couldn't get to the BIOS to flash it anyway).

You say your monitor doesn't come on. That implies the graphics card isn't starting, and that's very early in the boot-up process.

Is the fan in the power supply working? They are early candidates for clogging with dust, and seizing up. The switch-mode stuff then overheats and pops its clogs. No PSU fan = probable PSU fault.

I've fixed about half a dozen computers in the past 12 months (I do this for friends) where the power supply had died. I even keep a spare power supply in the cupboard (which meant I was back on line within a few minutes last time mine died).

EDIT: do you happen to have a spare graphics card you can plug in, if the PSU fan is running? That's the next check I'd make.

[Loose rivets]

Dismantling and bent pin. There's two logic inputs that come together.

That's just the kind of thinking that us old-timers used to use on valve electronics.

There is no need to have the monitor plugged in for the early tests.

Is there a disabled VGA graphics system on the MB? This might be reinstated to do the diagnostics - once you've eliminated the monitor.

Taking time and thinking. Just look at the MB for a while. Tiny screws etc. shaken under the edge. Anything that could have fallen onto cards or memory during the moving.

Are we to understand there are NO 'Post' beeps? Definitely remove the USB units, as I said, they are easy and carry a hard 5v. Certainly enough current to fell the PSU. Hard drive? I should have mentioned that when I talked of pulling the CD power lines. Same sort of procedure.

As far as I know, there are no 'special' USB plugs for required items like keyboard. Anyone know different?

I would be doubtful about the BIOS at this stage. Having said that, I owned a laptop that was a Sony write-off at two months old, that was just a BIOS chip problem. But very unusual. By the same token, the memory will come well down the list because it would not have been affected by the temporary packing away.


The dismantling, preceding the fault, is top of the list to focus on I would have thought. Go right round the 'rebuild' again, leaving out what you can.

[BabyBear]

Thanks for all the advice.

Having spotted the battery a couple of days ago I bought a new one yesterday and replaced it. At the time I did not know I would have to reset anything and found the same problem after replacement. Pressing F2 after powering up took me to a screen where I could change some settings. I discovered the date and time were wrong and reset these, the machine seems to start fine now (only tried a few times so far). The only issue now is that the image size seems to have to calibrate itslef to the monitor size on each start up, it didn't do this before.

Thanks again,

BB

[BabyBear]

Arrrrgh, so much for thinking it was sorted.

Machine worked flawlessly all day until I disconnected it to put it back under the desk and back to the same old trouble.

The diagnostic lights show a constant 3&4, which Dell explain as:
Memory modules are detected, but a memory failure has occurred.

They offer the following fixes:

If you have two or more memory modules installed, remove the modules, reinstall one module (see "Memory"), and then restart the computer. If the computer starts normally, reinstall an additional module. Continue until you have identified a faulty module or reinstalled all modules without error.
If available, install properly working memory of the same type into your computer (see "Memory").

I am happy working on the machine if someone would be kind enough to explain what the issue is, should it be an easy fix?

Thanks again,

BB

[Saab Dastard]

The issue seems to be a failed memory module.

The fix is to reseat, test and replace if failure confirmed.

A good way to test is to use MEMTEST (google it).

SD

[BabyBear]

Thanks SD, excuse my ignorance, is that simply the memory one would buy and install?

BB

[Saab Dastard]

Simply yes.

SD

[BabyBear]

Thanks again.

[Loose rivets]

Memory might be reduced to one strip. No go, try the other strip.

Although I said this, I have an uneasy feeling that this might be a byproduct of another fault. Just don't know what the noise would have been if it was just a deep down in the (memory) chip fault. Small smoothing/anti spike condencers do fail, and this would be enough to affect the power, but One does not see anything big enough on modern memory module/strip. But anyway, take the optimistic line and eliminate the bad module.

Firstly, have you got more than one? If not, it's off to the shops or a loan part. Secondly, have you changed these before?

I'll make the assumption that you haven't, that way I can get back to mixing my cement.


Although they are easy to change when you've done a few, you have to be careful when doing your first one. There are a few pitfalls.

They will only go in one way round. Note the little indent on the bottom where a couple of contacts are left out of the strip. This must be 'in phase' with the little bit of plastic in the socket.

They often require more pressure to put in than is good for the mother board. I tend to lead in with one end and feed it down from left to right - but only a tiny angle or it wont fit in the ends.

Try to get a clear idea just how far they are in now. This is important, and the clips at the ends should click in cleanly when it's fully down.

As SB says, there is a strong argument for just re-seating them/cleaning the contacts. So often the problem in the old days. Don't however touch the contacts with your fingers. Some of the voltages found on your fingers - even without static - are potentially (groan) damaging. In fact, try not to touch any part of the circuitry at all.

See how you get on.

[BabyBear]

Superb advice again, thanks.

Progress is being made.

Latest is I have run MEMTEST, as suggested by SD, and indeed it has found an error. Will be back out with the machine tomorrow and try to identify the memory.

I seem to remember the cost of memory is very low now? If this is the case my view would be to change all memory, does this make sense?

I don't have any spare memory, other than what is in the Inspiron 510m laptop I am currently using, presumably it will not be compatible?

BB

[Saab Dastard]

Generic memory is always cheaper than "model-specific" memory.

Just more difficult to ensure that you are getting precisely the correct module.

SD

[BabyBear]

Thanks again SD, I have used the Dell web site to establish the correct memory, cross checked against the link provided by StaceyF and ordered on line.

BB

[BabyBear]

Early days, but so far so good.

Memory arrived Saturday (having been ordered Friday) fitted it and so far running sweetly.

Thanks to all who replied, saved me a few bob.

BB