Be warned, this has nothing to do with LFS.

A while ago a friends' pc just froze (just during internet use, nothing strenuous or suchlike), and hasn't successfully booted since. The box is now in my custody as I attempt to repair it.

It's an Athlon64 (3400, I think), with an MSI 7903 motherboard, a pair of SATA drives, pair of optical drives, a gig of ram (I think), and some extra toys like tv card, etc.

As it's switched on, you can hear the hard disks spinning up, all the fans start and so on. However there's no POST beep, the IDE/SATA activity light on the front of the case stays on solidly, and there's no output to the monitor.

After disconnecting various components to try and isolate the cause of the problem, I noticed that disconnecting the optical drives had an interesting effect. With the hard disks being on SATA, only the secondary IDE channel is in use by the two dvd/dvdrw drives. When connected to the motherboard, the (optical) drives are dead. Can't even eject the tray. Disconnect one of them, and the tray will open and close as you'd expect, and the activity light on the case is only half as bright and flickers. Disconnect both and the activity light doesn't jam on anymore, but the computer still won't boot.

At no point is there any video output.

Anyone got any clues or ideas what to try next? I'm assuming there's something serious fubar with the motherboard, but overall I'm baffled.

tried another power supply? sounds like the current one might be dead or certainly on the way..

power to the DVD/CD ROMS comes from the PSU not the mobo, so that would be a good start.

As everything spins up but nothing from the mobo. I'd say that was at fault. That or the proc (if you have a dead proc you won't get to post). Flash the mobo, see if that works. If not then if you have a proc you can swap in and see if it posts. If not dead mobo, if it does dead proc.

[edit: After re-reading the first post, I agree with a dead PSU.]

Power supply would be my number one suspicion.

ok...

first, take out all pci cards, all ram except 1 stick, hdd and opticle drives (ide/sata and power). try post. if it still doesnt post then check the case speaker is plugged in.

plug in the power to 1 opticle drive and see if the drive boots (lights flash, it spins up, then sleeps). if the drive doesnt boot up, then swap out the psu.

if the drive did boot up then take out all ram sticks and attempt a post, if the case speaker works then it should beep continously (with brief pauses), we may not have a dead motherboard.

if its still not posting or beeping then swap out the cpu, or the motherboard.

Thanks for all the responses.

Firstly, to the best of my knowledge the buzzer/case speaker is working fine. It always used to, and apparently the first reboot after the freeze, it did give a beep pattern. Unfortunately my mate can't remember what the pattern of beeps was, just that it was different to the usual single-beep of a successful POST. However it didn't boot successfully, and all subsequent boots have been met with silence.

I have the manual for the motherboard, tried resetting the cmos but nothing changed. Of course the troubleshooting section is as useful as ever: "Symptom: computer fails to turn on correctly. Check: the power cable is plugged in correctly."

Regarding the power to the optical drives, I've tried switching molex connectors round between components and they all seem fine. The optical drives are healthy and behave normally when disconnected from their IDE channel. It's only when they're connected to the mobo that they just become dead.

Should there be any other symptoms of a dead PSU? It appears healthy in every way - any connected devices have power, and the ATI gfx card doesn't use a molex connector from the PSU for any extra juice - so all it's power comes from the mobo, and the gfx card does have power (well, the fan spins on it, anyway). Therefore it appears that power is going through the mobo correctly too (at least as far as the PCI-E slot is concerned).

@ dumbass, ta for the idea of taking out all the ram, hadn't thought of that. Will give it a shot when I nab a spare power cable from work tomorrow!

Thanks everyone for the help so far.

hmm, if there is a problem with the psu then try this:

turn the system on for about 120 seconds and then hit the reset button to cause a reboot (do not power it off and then back on). if the psu is on its way out then sometimes it can power on all the devices but not give enough juice for the cpu to turn on or the motherboard to post (causing an infinate loop of powering up), but after the psu has "warmed up" it might be able to post and/or boot windows.

if it does post/boot after a warmup then DO NOT use the pc until the psu is replaced, if the psu goes bang in a big way then it may damage any device attached to it




btw: taking out all the ram is only to test if the case speaker works

Thanks, I'd give that a shot too tomorrow, but there is no reset button.

Does the CPU fan spin up okay?

If the power supply is dying but not dead yet switch to onboard video (if possible) and disconnect all optical/SATA drives from the PSU, this might let the motherboard power up. If it does, take it from there re-connecting devices until it stops working again. Also if you have a multimeter check the output of the -5, -12v lines, if the PSU is failing the -5, -12v rails will be very low.

You say you've re-set the cmos? Via the pins near the battery? On most motherboards you can also restore factory settings by holding down "INSERT" before it reaches POST, but this doesn't work in all secarnio's.

Are the optical drives definately set to master/secondary? Or both to CS.

Last time I had this problem, the hard disk had a fault, and would only boot if set to CS and not master, this was causing it to not reach POST. I don't know if its the same for SATA but worth checking. I've also had this problem when the graphics card is faulty. Last thing I can think of is see if there's any goo around the capacitor bank near the CPU, its not that uncommon for one or two of these to start leaking after long use which causes bad problems.

You set master and slave for SATA in BIOS. There are no jumpers to change.

Ok, been trying out pretty much every possible combination of everything suggested above - various/all devices/RAM attached/unattached. Result is always the same - nothing. No POST at any point. Even with the RAM out and the PSU hooked up to nothing but the mobo (and the Coolermaster front panel thingy which in turn powers the CPU fan) and FDD, it won't post or boot in any way. Things have power and fans spin, etc, but it's not doing anything.

Time to choose - do I replace the mobo or PSU first? :nerd:

Quote from STROBE :

Ok, been trying out pretty much every possible combination of everything suggested above - various/all devices/RAM attached/unattached. Result is always the same - nothing. No POST at any point. Even with the RAM out and the PSU hooked up to nothing but the mobo (and the Coolermaster front panel thingy which in turn powers the CPU fan) and FDD, it won't post or boot in any way. Things have power and fans spin, etc, but it's not doing anything.

Time to choose - do I replace the mobo or PSU first? :nerd:

PSU, since you have a working PC while typing that message, that's the one thing you won't need to buy to test. Just take out yours and hotwire it in the other PC (don't properly install it, just hook up the cables).

yea that sounds like a dead psu to me.

Quote from STROBE :

Ok, been trying out pretty much every possible combination of everything suggested above - various/all devices/RAM attached/unattached. Result is always the same - nothing. No POST at any point. Even with the RAM out and the PSU hooked up to nothing but the mobo (and the Coolermaster front panel thingy which in turn powers the CPU fan) and FDD, it won't post or boot in any way. Things have power and fans spin, etc, but it's not doing anything.

Time to choose - do I replace the mobo or PSU first? :nerd:

I've only skimmed through this thread, so i don't know if it was covered or not. Have you tried reseting the BIOS by removing the battery or using the jumper? If that doesn't clear things up I would suspect the PS as well. You can check it if you have a volt meter and the color code (or pinout) for the conductors and their respective voltages is available. You typically need to bridge the conductors in the bundle which turn the PS on. Then you can measure the various colored pairs and verify their voltages. Typically one or more will just be plain dead if the PS is cooked. If this doens't sound like fun to you, it's much easier to simply swap out the PS, although I don't actually install it in the chasis until I know it's solved the problem. Good luck!

Reset your BIOS and try that, but im honestly tempted to say its the CPU. I had exacly this problem when my XP 2400 died.

did I miss the bit where it started to look like a psu failure?
Sorry if it's been said, but if it won't POST with a new vid card and stick of ram and everything else unplugged, 95% it's a dead motherboard, the other 5% psu, cpu, or other random option.

OK...

First of all: in the end EVERY single component gets its power from the PSU. Maybe not directly but also the mainboard doesn't power itself in some magical way.

Had to say that after reading several times in this thread about the difference if something got its power from PSU or MB. There is no difference if it's the psu which is at fault...

@ STROBE: it's always difficult to make diagnostics on a somehow damaged PC if you don't have it lying before you. For example I have already seen a faulty IDE cable completely preventing a PC from even POSTing. Something like this is impossible to guess from afar...

So if a fault is not obvious to see (like for example everything that should be cooled is covered with dust...) the best thing to do is to unplug things step by step and see if the problem disappears at some point. And if you already stripped the box down to only the very necessary stuff (MB, CPU, RAM, VGA, PSU) and the fault still remains you can only see if you have some parts to temporarily exchange the rest piece by piece. This is necessary since without most of these parts the PC won't POST anyway so just taking away RAM completely will not make you see anything.

But I guess you have a PC yourself, so you might have some parts to exchange - and like suggested many times before I would also go for the PSU at first. Like rabidmaddog already said there is no need to mount it inside the case - just plug everything in where it should be and see if it works. I wonder why you haven't done that already after every second suggestion in this thread told you to see if it's the PSU...

You know, a spinning fan does not necessarily mean that there is enough power to also run a CPU/GPU which need A LOT more power. Also a PSU has different outputs with different voltages and sometimes only one of them can be faulty causing the whole system to fail.

If all of this doesn't get you anywhere, there is still the other way round that you can try. If you have a flawlessly working PC you could exchange its parts piece for piece with the ones from the damaged one and see at which point the working PC stops working...

I know this can be a lot of screwing and mounting and stuff and can take a long time but if you have absolutely no hint why the PC stopped working a simple try-and-error-process is anything you can do.

I hope I could help you and make myself clear because my english is not quite perfect in some of these technical terms...

Anyway - I wish you good luck in finding the error...

P.S.: ah! I forgot! There are parts that are not directly powered by the PSU - it's the RTC and the CMOS...

Sounds exactly what my P4 2.5 did. I stripped it down to hardly nothing, checked with a PSU from another working PC, and checked all components other than MB and CPU in the other PC. Narrowed it down to the MB or CPU, which I didn't have access to spares to check either. Was going to replace with a new MB/CPU combo, but just ended up buying an entire PC. Sure it's off the shelf, but for what it would cost to replace just the MB/CPU comparable to the AMD 64 3500 I got would only have been slightly less money. And a new 17 inch monitor came with it to replace my original 11 yr old monitor as well as a new printer to replace my long broken one.