GA-P55A-UD3 boot loop, no post, no beeps

jcolvin

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Aug 20, 2010
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I've got a new build set up based around the GA-P55A-UD3, core i5 760, ocz platinum 1333MHz, Cooler Master UCP 1100W

Every time I hit the power button the fans and hard drive power up, but the screen doesn't initialise let alone display anything. after a couple of seconds the system shuts itself down and then about 6 seconds later it restarts again.


I installed a system speaker but i get no beeps (tried 2 different ones) and all the cables are plugged in correctly. I have tested with a different power supply (corsair TX650) with the same result. I reset the cmos using a jumper and also removed the battery.

I tried breadboarding the system and no matter what is connected i get the same reboot pattern, with the exception of if the cpu has no power when the time running before shutdown is very short (~0.5s)

Ideas so far:

The memory is bust or not being recognised (this should cause a beep code however)
The cpu is broken (already checked for bent pins)
The motherboard is broken

Any further ideas?

Thanks

John
 

John_VanKirk

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Hi John,

Start testing the motherboard from the bottom up. I'd take out the Graphics Card, and the RAM. The start it up with only the CPU and see if you get any beep codes. You should get the beep code 1 long 1 short indicating a Memory problem (like no RAM) or 1 long 2 short indicating the graphics card is missing.

Make sure the 24 pin power connector is seated properly and the 8 pin 12V ATX accessory CPU power connector is connected.
Make sure your small speaker is functioning.

If you get a beep code, then turn it off, and install the RAM, and try again.
If you get a beep code, install the graphics card and try again. If no beep codes after inserting the graphics card, it could mean an initialization problem with the graphics card.

If you don't get any beeps at all after testing, I'd very carefully remove the CPU and with a magnifying glass, inspect the socket for any bent or misalligned pins that could be the problem.

Usually no beep codes at all with no hardward devices installed means the MB is seriously ill.
 

jcolvin

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I have done all of the above. Should a motherboard give a beep code with no cpu installed? I seem to remember from ancient builds that it should, but it's been a long time and it's not a situation I generally put myself in
 
No. No CPU, no beeps.

A Gigabyte motherboard with no memory should give a series of long single beeps.

Work through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-posting-boot-problems
I mean work through, not just read over it.

Breadboard - that will eliminate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboarding

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to.

You should hear a series of long, single beeps indicating memory problems.
Silence indicates a problem with (in most likely order) the PSU, motherboard, or
CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

Now, just verifying that you get to this point and you get silence. You have swapped out PSU's with a very good one. If the PSU came from a working system, it is a known good one. So, because CPU's seldom fail out of the box, I'd try another motherboard.
 

jcolvin

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I've completed all the steps in the first link and have already breadboarded the system (as mentioned in the OP)

As I get no beep codes from any situation, I think I'm gonna return the motherboard as broken (bought on ebay) and get a new one. Hopefully that'll solve the problem. If not then I'll replace the CPU
 

John_VanKirk

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Hi John,

If you still hear no beeps, one thing you can do to check out the CPU is take it down to a local shop and ask if they will put it in one of their bench boards. Usually they will, and if it POSTs or you have some graphics display you know the CPU is good, and feel confident about returning a defective motherboard for a good one.
 

Admiral_Cecil

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Dec 12, 2005
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In my P55A-UD7, I discovered 2 of my dimm slots (1 and 3) no longer function correctly thus the PC refuses to power on. I found that out by testing 1 slot at a time.
 

wataytay69

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Mar 27, 2012
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Did you ever resolve this issue?

Buddy of mine has the same mobo with similar issues and no recent changes in hardware. Tested his PS on one of my boxes and it works great.

Thanks in advance! :hello: