Help Pc is not making sense

warnea1984

warnea1984

warnea1984

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26 Jan 2005
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826
Well I seem to have a puzzle on my hands if some one could please help.

Recently my pc in my spec failed to turn on. Looking at my motherboard I could see the orange power led was on.

Right I thought I have power, so unplugged the motherboard power cable and jump started the psu. Now all the fans (connected via motherboard), and HDD and DVD Roms started up. So I thought the problem was with either the motherboard or the power switch. So I got a jumper and crossed the power on pins on the motherboard and still nothing. Right I though its the motherboard got to be.

So off I went and purchased a new A8N-SLI Deluxe. Removed all the componets from the DFI motherboard and transferred them to the ASUS plugged it all in and again the green power LED is on.
Pressed the power button and nothing. Ok i thought so I started unplugging hardware HDD and DVD Roms, keyboards mice everthing. Tried the power button again and nothing. Then I removed the gpu and tried again and again nothing.

So i thought better check the PSU again, so with the PSU plugged into nothing I jump started it. Now only the rear fan spins up. So i thought lets get the multimeter out. Tested all the rails and they all displayed 0v and this is where it gets weird, after playing around with the psu I discovered that if the psu is plugged into a DVD-ROM and jump started there rails all supply a current. Testing the psu with the multimeter all the rails had voltage, and now both fans were spinning. So I am confused, why would my psu do this?

Oh and my psu is a hiper 580w modular thingy.

Also if its not the psu and not the motherboard and its not a HDD or ROM drive, then it must be the CPU right, but correct me if i am wrong the CPU shouldn't stop the motherboard from booting.

I know this has been a long post and if your still reading thank you and I beg you please help.
 
I had problem with my computer that all the fans were spinning and leds on the motherboard, turned out to be the cpu that failed.
 
have you tested the psu with a multi metre when the power is switched on, on the PSU and the light on the motherboard is on?

I doubt its the CPU but you could remove this and see if the fans spin just to illiminate it from the problem.

It does sound like the PSU is faulty as you say it works when you jump start it but doesnt power up the system - maybe it just doesnt supply enough power to start the board + components.

If removing the processor doesnt help the situation then keep all the additional components including any PCI cards, hard disk, dvd-roms etc disconected and reconect them until you experience the problem with no fans spinning then you will know where the fault lies....if that doesnt work test a known working PSU on the system IMO.

When you put a jumper over the pwr_on connection that wouldn't have started the system anyway as between those two points requires just a single connection for a split second to start the PSU and system up and not a constant connection that would be made by using a jumper.

Make sure the board isnt shorting out on the case and that the CPU fan is plugged into the correct header on the motherboard - some boards wont start if this isnt right.

ghgh
 
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ghgh said:
have you tested the psu with a multi metre when the power is switched on, on the PSU and the light on the motherboard is on?
ghgh
Click to expand...

Yep and the stand by voltages are all their and present on both the purple and green wires.

ghgh said:
I doubt its the CPU but you could remove this and see if the fans spin just to illiminate it from the problem.
ghgh
Click to expand...

Took the cpu out and still no fans not even the southbridge fan.

ghgh said:
It does sound like the PSU is faulty as you say it works when you jump start it but doesnt power up the system - maybe it just doesnt supply enough power to start the board + components.
fans spin just to illiminate it from the problem.
ghgh
Click to expand...

ghgh said:
When you put a jumper over the pwr_on connection that wouldn't have started the system anyway as between those two points requires just a single connection for a split second to start the PSU and system up and not a constant connection that would be made by using a jumper.
ghgh
Click to expand...

I tried just shorting the pins with a quick touch of the end of a screwdriver, should that have worked?

ghgh said:
Make sure the board isnt shorting out on the case and that the CPU fan is plugged into the correct header on the motherboard - some boards wont start if this isnt right.
ghgh
Click to expand...

I’ve removed the motherboard from the case and its now on an anti static matt. Its got to be the psu either that or I’ve got two motherboards from different suppliers with the same problem.
 
I had exactly the same problem. i thought it was my Hiper PSU - motherboard light was on, but wouldn't power up.

I replaced the PSU with a cheap one from a local retailer, but this didn't work. I told the shop I would return it if it didn't work when I bought it, so this cost me nothing - you could try doing this?

The quick touch with a screwdriver should work.

In the end I replaced the motherboard, cpu & memory, but still could not get the power on.

I shorted the PSU and everything sprang to life. Eventually, after swapping back and forth between my old MB, CPU, memory and the new stuff, it eventually worked. Try only hooking up the necesary stuff - no hard drives, DVD, case fans etc

Try to get a cheap PSU replacement, if that works you can replace with a better quality one. If it doesn't then I'd reckon on it being either the MB or maybe graphics card.
 
Mike_J_Smith said:
Try to get a cheap PSU replacement, if that works you can replace with a better quality one. If it doesn't then I'd reckon on it being either the MB or maybe graphics card.
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We I’ve got two motherboards now and neither worked, will a motherboard boot without a cpu or RAM installed, I don’t mean into windows just boot and provide a beep code?

I’ve taken everything out the cpu all HDD and the RAM. Still nothing from the motherboard. Hell even taken the motherboard out of the case.

I took my psu to another machine and managed to get the other machine to boot.
 
CPU no it will be totally lifeless with no cpu, but yes you should get beep codes with ram missing, or gpu missing.

The voltage on your PSU with zero load is not a huge surprise, many switch mode PSU's need a minimum load to stabilize, I normally use an old hard drive which I dont care about.
 
Well took my DFI motherboard that I tried to replace and I plugged the hiper PSU into the motherboard using only the 24pin plug and pressed the on board power switch and got nothing. This was with no cpu ram or any thing installed.

Took the same motherboard to a mates plugged in only the 24pin motherboard connector from his tagen power supply and it jumped to life. All 4 BIOS indicator lights were on signalling that there was no cpu, ram or gpu etc plugged in, even got the bleep codes.

So I am beging to think that although the hiper psu's rails haven't failed the control board the interepts the power up sequence is bust.

Although still puzzles me that the pse managed to boot up a matx motherboard no problems, that was a 20 pin motherboard.

Gona purchase a new psu see if that helps, can any one reccommend one, I planning a new build next year so I figure I'll be better of getting a decent psu that I can use in the new build. My budget is around £100 and I would prefer all cables be sleeved can't stand bare cables. Modular would be nice but not essential.

Recommendations please.
 
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I got one when they first came out, so had no idea of the build quality, but lesson learnt one less manufacturer to use.

So my next psu wont be a hiper, other than that I looked at the

Thermaltake ToughPower 750W Modular Power Supply
and the
Corsair HX 620W ATX2.2 Modular SLI Compliant PSU
 
OK now this topic I found useful but has me confused now :| I am experiencing same issues but I know its not my CPU as I purchased a brand spanking new Quad Core Q6600 and it my system isn't booting. However my chasis cases, heatsink, LED on both graphics and mobo are lit but no BIOS screen! Looking to buy Gigabyte GA_P35_DQ6 from Overclockers but having read this is got me thinking could it be the PSU? Its an Enermax noisetaker but as I said everything is getting power but I am not getting any POST.

I put in all the essentials ONLY like CPU, heatsink, mobo and PSU connected and NOTHING else but still no POST. Put the RAM in and still nothing. HDD were not connected, graphics not connected but getting no POST. My motherboard dead or PSU?

Thought I had the problem but reading this has got me really confused :(
 
PikKOn said:
OK now this topic I found useful but has me confused now :| I am experiencing same issues but I know its not my CPU as I purchased a brand spanking new Quad Core Q6600 and it my system isn't booting. However my chasis cases, heatsink, LED on both graphics and mobo are lit but no BIOS screen! Looking to buy Gigabyte GA_P35_DQ6 from Overclockers but having read this is got me thinking could it be the PSU? Its an Enermax noisetaker but as I said everything is getting power but I am not getting any POST.

I put in all the essentials ONLY like CPU, heatsink, mobo and PSU connected and NOTHING else but still no POST. Put the RAM in and still nothing. HDD were not connected, graphics not connected but getting no POST. My motherboard dead or PSU?

Thought I had the problem but reading this has got me really confused :(
Click to expand...

Do your fans spin up when you press the power button on the case?
 
PikKOn said:
Yeah all my case fans make the noise, my graphics fan also spins/makes noise, heatsink spins and makes the noise but no POST beep from motherboard :(
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Sounds more like the motherboard, I don't even get the fans spinning up unless I jump start the psu.

Try taking your psu out of the case and use it in another pc, as thats easier than removing the whole motherboard.
 
Ive had very similar problems recently. I also bought a replacement m/board but still no joy. I replaced both sticks of ram with a single stick of cheapie and bingo it POSTS. So both sticks of ram are dead! Now someone suggests that the m/board or the PSU may be to blame.
I can test the PSU ( a good quality Epsilon 700W ) but Ive no idea how to test the m/board.
 
Well lucky for me my brothers brother in law has a system that is DDR2 compatible thus tested my RAM and hey it works, my CPU is brand new so has to work, tested my PSU on another machine and works and graphics card alse tested and works so mobo is dead :(
 
sounds exactly like the problems im having :( you have the same psu as me too!

a wee green light shows on the motherboard, but when i press the power button nothing happens :(

i think its the psu... sometimes it wouldnt start straight away, would need to push the power button many times before it came on! Isnt my power switch, done this in my old case too! lol
 
craig_kennedy83 said:
sounds exactly like the problems im having :( you have the same psu as me too!

a wee green light shows on the motherboard, but when i press the power button nothing happens :(

i think its the psu... sometimes it wouldnt start straight away, would need to push the power button many times before it came on! Isnt my power switch, done this in my old case too! lol
Click to expand...

Yeap sounds just like my psu, just seen a few reviews for gigabytes new 800w PSU, looks awesome and looking at the reviews the heatsinks inside the psu are copper and not alu, I think thats the first time I've seen copper inside a psu.

Check out the review at Bit-tech
 
warnea1984 said:
Yeap sounds just like my psu, just seen a few reviews for gigabytes new 800w PSU, looks awesome and looking at the reviews the heatsinks inside the psu are copper and not alu, I think thats the first time I've seen copper inside a psu.

Check out the review at Bit-tech
Click to expand...

Copper is actually a better thermal conductor than aluminium I think, so is actually preferable to use for heatsinks/cooling. Unfortunately, it's also more expensive than aluminium, which is probably at least partly why you tend to find Al being preferred/making up the majority of heatsink assemblies.
 
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