• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

PC powers up but doesn't show bios

T

tcl70

Junior Member
I have upgraded my old rig

Mobo: Gigabyte GA-Z68X-UD3H-B3 ver1.3
CPU: Intel Core I5 2500k
Mem: Corsair Vengeance CML8GX3M2A1600C9 Low

PSU: Zalman ZM500-HP (re-used)

The Mobo requires a ATX-12V_2x4 (8pin) cable but I didn't have those from the Zalman PSU so used 2x ATX 12V (4pin). Does 8 pin 12V even exist for non PCI-E videocard power?

I have exchanged the Mobo, Memory and CPU and kept the PSU. Now trying to boot up. CPU-Fan is running and LED's of mobo turn on but bios screen is not appearing. LED's are flashing on Mobo, some ticking or short beeps can be heard but not as loud as normal pc-speaker.
Nothing else is connected to the motherboard except for the components above. I'm using the onboard videocard for display.

Tried to remove the memory and boot up : same result, nothing happens
Removed the cooler and reseated the CPU: same result, nothing happens
Checked another Mobo on the PSU: that Mobo starts up means PSU is ok?
Checked the monitor on another PC: image shows up

Can it be the PSU? or is the Mobo or CPU a DOA?
I don't have newer PSU's so would need to purchase one.
What about the 8 pin ATX cable is this correct?

Thanks.
 
Last edited:
two 4 pins are fine for 12V aux CPU, later PSU have 8 pin or both
they are keyed and can only go on 1 way, both lock tabs same side
make sure HSF is on 4 pin CPU header just above 1X PCIe slot
the onboard is prob disabled by default in bios, set to PCIe/PCI as first boot, not iGPU. So use a reg vidcard to start

Edit: Now this is funny PCI is default - LOL!
Guess you'll need to start with AGP card haha
Did you try DSUB blue 15 pin Z68 port?
ZyUdA.jpg
 
Last edited:
Ya, my Corsair TX 650V2 has two 4pin's together. I guess this is to allow the PSU to work on older boards with only a 4pin connector. Anyways, ya thats fine. two 4's is the same as an 8.

Youre saying you already exchanged the mobo and cpu once and its still happening? Exchanged from previously faulty parts or are you saying you built a new system?

Anyways, if you take the cpu out and it still doesnt do anything, Id guess bad motherboard?

Could be something mounted maybe causing it to short out, hard to say.

I recently accidentally bent the cpu pins on an old mobo in the process of removing it and that basically gave me the same thing youre experiencing. The mobo wouldnt even post, even with no cpu in.

If its easy to do, replace the mobo unless you know its good. The chances of a CPU being bad are extremely small, so that would be my last guess.

If that is a really old PSU, I suppose that could be it. I dont know much about zalman PSU's but I never recommend using severely old or bad quality PSU's. It sounded like your PSU was fine before until you got a new mobo, cpu, mem, so Id guess the PSU isnt the problem.
 
Last edited:
bankster55 said:
make sure HSF is on 4 pin CPU header just above 1X PCIe slot
...
Edit: Now this is funny PCI is default - LOL!
Guess you'll need to start with AGP card haha
Did you try DSUB blue 15 pin Z68 port?
Click to expand...

HSF = High speed fastener? not sure what you mean here. The CPU cooler is mounted and connected, fan's are running.

I tried connecting the PCIe graphics card with 6 pin PCIe powersupply connected. -> same problem still no image.
and tried the DSUB blue 15 pin on the Z68 port -> same problem no image

Besides the no image also the keyboard lights are still not lit, when i push in a USB stick i can see that there is at least power on the USB ports but don't get any keyboard response.

Fallengod said:
Youre saying you already exchanged the mobo and cpu once and its still happening? Exchanged from previously faulty parts or are you saying you built a new system?

Anyways, if you take the cpu out and it still doesnt do anything, Id guess bad motherboard?

Could be something mounted maybe causing it to short out, hard to say.
Click to expand...
I connected the current PSU to the old Mobo to check the PSU and there it still works. the idea was to upgrade the pc with a new mobo, cpu, mem etc.
Is it allowed to take a CPU out and run a Mobo without CPU?
No shortcuts, I put the mobo outside the case on a piece of foam.
 
Last edited:
HSF = Heat sink fan
I didnt ask if fan was running
I said make sure HS fan is plugged into marked 4 pin "CPU FAN" header

Lemmee guess, you are using CoolerMaster Hyper 212+ or Corsair H-80
 
bankster55 said:
HSF = Heat sink fan
Lemmee guess, you are using CoolerMaster Hyper 212+ or Corsair H-80
Click to expand...

Scythe mugen2 and i regret it, it's a huge cooler and difficult to mount due to it's size. Liked the old coolermasters more.

Anyway, found what the problem was. For some reason the PSU didn't deliver enough current or not stable enough. For the old mobo apparently it was good enough for this one it just didn't go to bios despite that it was a 500W PSU and all led's were lit and fans were on.

thanks all.
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top