Another computer broken and i'm stumped for now.

[theo]

Been a while since i've used the hardware section of the forum but i need you guys once again. Simple problem to explain;

Hardware i'm using:
-Sapphire ATI Radeon HD 5850 1024MB GDDR5 PCI-Express Graphics Card
-Intel Core i5 750 2.66Ghz (Lynnfield) (Socket LGA1156) - OEM
-OCZ Obsidian 4GB (2x2GB) DDR3 PC3-12800C9 Dual Channel (OCZ3OB1600LV4GK)
-Western Digital Caviar Green 1.5TB SATA-II 64MB Cache - OEM (WD15EARS) ***replaced with Corsair Force 3 60GB***
-Gigabyte GA-P55-US3L Intel P55 (Socket 1156) DDR3 Motherboard
-Microsoft Windows 7 Home Premium 64-Bit - OEM (GFC-00599)
-OCZ ModXStream Pro 600w Silent SLI Certified Modular Power Supply

[edit]: It was shipped in February 2010 so i asusme all the warranties have run out.

I was playing some fear3 with a friend and after a while the pc is up to speed, fans at probably 40% load but it's a hot day today. Then computer then turns off, just a black screen, it turns back on automaticly so i think it's just a graohics card overheat which i still get occasionaly. But at this point the fans are running very loud, there's not bios beep, no boot screen and the gpu bios hasn't kicked in an lowered the fan speed.

In summary, no boot signs and graphics card fan is at 100%.

At this point i go through a few things, turning on without graphics card, ram, ancillary hdds plugged in. Tried with a different graphics card and nothing. The only response i can get from the computer is a loud continuous beep/whistle when there are no power cables plugged into the graphics card.

This leads me to think i've narrowed it down to the cpu, psu or motherboard. I'm deciding to leave out the paperclip test because fans are running so there's current flowing. The only other thing left is four red/orange LEDs just above the memory slots with the text 'PHASE LED' near them.

I'm just posting this to see if anyone has any idea about what's wrong before i take it to my friends on friday to some more testing, as he has a multimeter and the same mobo/cpu combo as me.

 

[OptimaLnrg]

Just replaced the same psu as yours for my brother the other week as it was sounding a bit dodgy.

When you go round your mate's house try out his psu in your system.

Does the mobo have an LED poster? I'm guessing not..

Try the vga-out on the mobo to rule out the gpu. See if it gives any beeps out then and look the sequence up in the manual.

 

[theo]

Just replaced the same psu as yours for my brother the other week as it was sounding a bit dodgy.

When you go round your mate's house try out his psu in your system.

Does the mobo have an LED poster? I'm guessing not..

Try the vga-out on the mobo to rule out the gpu. See if it gives any beeps out then and look the sequence up in the manual.

Trying the psu was on my todo list, along with cpu. No onboard vga, but as i said i tried it with both a different gpu and no gpu installed to no avail.

After some more googling of the PHASE LED thing, it seems they're a meter which tells you the activity of either the cpu or mainboard, so i'm assuming it's the current going through the cpu. This leads me to think it could be a short somewhere or the above psu problem.

 

[Purgatory]

What you explain there sounds like a classic PSU failure on some rails or the use of a cheap PSU.

Try a PSU first before you pull apart the rig and only to find it was the PSU that has failed, a PSU sending current to other parts of the system like fans etc does not still mean it is working correctly. I have had many PSUs that show the fans spinning and motherboard lights up but no POST at all.

 

[theo]

What you explain there sounds like a classic PSU failure on some rails or the use of a cheap PSU.

Try a PSU first before you pull apart the rig and only to find it was the PSU that has failed, a PSU sending current to other parts of the system like fans etc does not still mean it is working correctly. I have had many PSUs that show the fans spinning and motherboard lights up but no POST at all.

Okay thank you, just reinforcing that as my expected problem. A little happier since psu is generally cheaper than the other components. But i've been going by the simple rule that the psu is probably the most important component in a build, doubly so for the shoddy electrics in my old house.

On a side note, how resiliant would a psu, because i think i have an old 550w corsair in my cellar, but it's probably damp/mouldy being in there. Think there's a chance it could be dried out and still workable. I mean it's in a plastic sack but probably perished. In other good news my friend's old man literally has like four psus lying about because he's been having ome troubles recently.

 

[psychodil]

Yes I would say PSU problem as well. It sounded like a GPU death but you said it won't work with another GPU installed. Have you tried resetting the bios on the mobo?

 

[theo]

Yes I would say PSU problem as well. It sounded like a GPU death but you said it won't work with another GPU installed. Have you tried resetting the bios on the mobo?

Reseting the bios was the first thing i tried, there were only two pins and they were seperated from the text so it took a while, a while to find a jumper too but that didn't affect it at all. I found the Corsair HX520w from my old pc at it looks like it's in good condition for now so i'll test that shortly.

I'm guessing 520w will be enough to drive my pc plus SSD 2x HDD and DVD drive?