PC Failing to boot..
Discussion
Some of you might remember a thread that I started back in July (see http://www.pistonheads.com/gassing/topic.asp?t=190870) regarding my PC going wrong after a lightening strike. Well, the insurance paid up (the 'cash' due the repair quote being silly) and I decided to try to fix it myself.
I managed to get a 2nd hand MB from ebay and have swapped out the old one (but still using the replacement CPU and RAM that came with the MB). However, I still have exactly the same problem in that the machine powers up (spins HDD and CDs) but doesn't get near to either sounding like booting or displaying anything on the screen.
This leads me back to thinking it is either a knackered PSU.
Any further thoughts? Anyone got a spare PSU I can try?
I managed to get a 2nd hand MB from ebay and have swapped out the old one (but still using the replacement CPU and RAM that came with the MB). However, I still have exactly the same problem in that the machine powers up (spins HDD and CDs) but doesn't get near to either sounding like booting or displaying anything on the screen.
This leads me back to thinking it is either a knackered PSU.
Any further thoughts? Anyone got a spare PSU I can try?
If your internal peripherals are firing up, that would appear to indicate that power is being delivered properly. I would have thought that if the PSU were damaged, nothing would work at all, unless just one of the rails were damaged - do you have access to a multimeter to test it?
Also, do you get any beeps as the machine tries to boot? That can give an indication as to the nature of the problem - the number of beeps usually corresponds to BIOS, processor, memory, or graphics error. Another thing to consider - does your monitor receive a signal of any kind, or does it just stay in standby mode?
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Also, do you get any beeps as the machine tries to boot? That can give an indication as to the nature of the problem - the number of beeps usually corresponds to BIOS, processor, memory, or graphics error. Another thing to consider - does your monitor receive a signal of any kind, or does it just stay in standby mode?
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will do some more multi-meter testing tonight. Did some when had original problem a couple of months ago and did pick up voltages on the MB but was not checking for accuracy of these nor checked all outputs of the PSU.
No beeps (other than those covering my swearing at the machine
).
I don't get any output to monitor at all (doesn't surprise me as the PC would need to boot at least too bios to display something wouldn't it?
>> Edited by cirks on Wednesday 21st September 11:38
No beeps (other than those covering my swearing at the machine
). I don't get any output to monitor at all (doesn't surprise me as the PC would need to boot at least too bios to display something wouldn't it?
>> Edited by cirks on Wednesday 21st September 11:38
OK, try this - I'm assuming you are familiar with dealing with electricity and know the precautions. Don't blame me if you electrocute yourself 
Disconnect the PSU from the PC entirely. On the motherboard connector, use a short piece of wire to short the green lead to one of the black leads. This will make the PSU come on as soon as you plug it in. You can then test for voltages on the connectors as follows:
mobo connector - see here... http://pinouts.ru/data/atxpower_pinout.shtml
peripheral connectors - yellow = 12v; red = 5v
You will see slightly lower figures than those quoted as the PSU is not under load. This can be corrected by a balance resistor, but for current purposes, as long as you get a reading approaching these values, the PSU should be OK.
If you are not geting a beep code at all, first up check the speaker is properly connected! Try removing as many components as you can - take out any sound and network cards, extra memory etc. Try running with just VGA, CPU and 1 stick of RAM (try swapping them over as well). If that still doesn't help, the CPU, graphics card or memory was probably fried. Try borrowing alternatives if you can, to gradually eliminate the possibilities, or testing your suspect components in another machine.
[k]
Disconnect the PSU from the PC entirely. On the motherboard connector, use a short piece of wire to short the green lead to one of the black leads. This will make the PSU come on as soon as you plug it in. You can then test for voltages on the connectors as follows:
mobo connector - see here... http://pinouts.ru/data/atxpower_pinout.shtml
peripheral connectors - yellow = 12v; red = 5v
You will see slightly lower figures than those quoted as the PSU is not under load. This can be corrected by a balance resistor, but for current purposes, as long as you get a reading approaching these values, the PSU should be OK.
If you are not geting a beep code at all, first up check the speaker is properly connected! Try removing as many components as you can - take out any sound and network cards, extra memory etc. Try running with just VGA, CPU and 1 stick of RAM (try swapping them over as well). If that still doesn't help, the CPU, graphics card or memory was probably fried. Try borrowing alternatives if you can, to gradually eliminate the possibilities, or testing your suspect components in another machine.
[k]
[quote=[k]ar|]OK, try this - ........
[/quote]
many thanks. Will test the PSU tonight. Electricity doesn't scare me, it's just the botch jobs that someone had done to the ring main in our house that scares me! Was fine after I corrected it and then ended up getting most of it rewired by a professional!
Anyway, I digress...
The replacement MB I bought came with CPU, fans and RAM so, I have effectively swapped all of those over from my original ones. To me, this still points to PSU unless some more spooky going on (eg graphics card or something else shorting?)
[/quote]
many thanks. Will test the PSU tonight. Electricity doesn't scare me, it's just the botch jobs that someone had done to the ring main in our house that scares me! Was fine after I corrected it and then ended up getting most of it rewired by a professional!
Anyway, I digress...
The replacement MB I bought came with CPU, fans and RAM so, I have effectively swapped all of those over from my original ones. To me, this still points to PSU unless some more spooky going on (eg graphics card or something else shorting?)
Well... that helps alot. It's almost certainly your graphics card if the CPU and RAM has also changed. By a process of elimination, the VGA appears to be the only remaining part (aside from the PSU) retained from the original machine, yet the symptoms remain the same. It would also account for your monitor receiving no signal at all.
Do, of course, check your PSU, but on the strength of what you have said, I would be more tempted to say the culprit is the graphics card.
[k]
Do, of course, check your PSU, but on the strength of what you have said, I would be more tempted to say the culprit is the graphics card.
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Not really, unless you have a chum nearby who would let you try out your card in his machine. You don't need to install drivers or anything - if it brings up a picture in the BIOS, that will be enough for a diagnosis. That would save having to buy a new card, but otherwise, there's not much alternative than to test it to confirm for sure what's wrong.
What is the damaged card and what are you going to use the machine for? You can pick up an el-cheapo VGA card new for under £50 if needs be.
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What is the damaged card and what are you going to use the machine for? You can pick up an el-cheapo VGA card new for under £50 if needs be.
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[quote=[k]ar|]
What is the damaged card and what are you going to use the machine for? You can pick up an el-cheapo VGA card new for under £50 if needs be.
[/quote]
The machine is 6 years old and had already been replaced by a more up to date powerful one so it's only going to be used as a server and possible media store. Therefore graphics quality not important at all! The existing card is a Matrox Millenium 400 (I think!)
What is the damaged card and what are you going to use the machine for? You can pick up an el-cheapo VGA card new for under £50 if needs be.
[/quote]
The machine is 6 years old and had already been replaced by a more up to date powerful one so it's only going to be used as a server and possible media store. Therefore graphics quality not important at all! The existing card is a Matrox Millenium 400 (I think!)
Well, just checked all the PSU voltages and everything is as you listed (exception is the blue and white readings are the opposite to the link you provided but that might be down to the PSU itself. However, no dead or particuarly low/high readings.
So, no to test the graphics card. I need to see whether the even older PC I have in the loft has a compatible card otherwise I'll be on the scrounge for one from somewhere!!
Thanks for your help so far Karl.
So, no to test the graphics card. I need to see whether the even older PC I have in the loft has a compatible card otherwise I'll be on the scrounge for one from somewhere!!
Thanks for your help so far Karl.
Ok, how stupid do I feel?
Suddenly realised that I hadn't checked the pc with everything removed bar the graphics card,cpu & ram. Guess what, worked straight away. Gradually added the other PCI cards back in and discovered that it was the network card that caused all the problems! That's now out, spare wireless card in and works fine.
Many thanks, especially to Karl for assistance. Anyone wanting to point out that this is what I should have done first is free to do so
Suddenly realised that I hadn't checked the pc with everything removed bar the graphics card,cpu & ram. Guess what, worked straight away. Gradually added the other PCI cards back in and discovered that it was the network card that caused all the problems! That's now out, spare wireless card in and works fine.
Many thanks, especially to Karl for assistance. Anyone wanting to point out that this is what I should have done first is free to do so
You should have done that first 
Wow - I would never have thought that a network card would cause that kind of error, but it just goes to show how important the "back-to-basics" principle is when diagnosing PC problems. That and looking at what has changed since something stopped working. At least you are up and running again now, though.
Glad to be of help!
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Wow - I would never have thought that a network card would cause that kind of error, but it just goes to show how important the "back-to-basics" principle is when diagnosing PC problems. That and looking at what has changed since something stopped working. At least you are up and running again now, though.
Glad to be of help!
[k]
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