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LED Blinking on MOBO. no boot

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January 24, 2011 6:28:05 PM

Hi
I recently assembled a PC
-AMD Phenom II X4 925 Deneb 2.8GHz Socket AM3 95W Quad-Core Processor
-ASUS M4A87TD EVO AM3 AMD 870 SATA 6Gb/s USB 3.0 ATX AMD Motherboard
-G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (
-Rosewill Blackbone Black Steel / Plastic ATX Mid Tower Computer Case
Seagate Barracuda 7200.12 1TB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive
-OCZ StealthXstream II OCZ600SXS2 600W ATX12V v2.2/ EPS12V 80 PLUS Certified Power Supply

It was working for about a 2 month or so and doesn't boot any more. There is neither boot beep nor any display. No components are working including fan

On the MOBO I can see the Standby LED blinking with a very faint tick sound.

Tried removing power and BIOS battery
but doesn't help. Some suggested removing USB on a forum.

I guess this is a PSU problem

Please provide suggestion to troubleshoot the problem.
Thanks in Advance

More about : led blinking mobo boot

a c 126 à CPUs
January 24, 2011 6:40:25 PM

Well it almost sounds like a bad PSU but those OCZs are not bad. They shouldn't die off tht fast. But to test if it is the PSU, I would suggest removing everything from the mobo except the CPU and one stick of memory. Then try booting it up.

If it boots it can show that the PSU isn't able to supply the needed watts. If it doesn't boot it can still mean PSU but it could also mean the mobo went bad or something else major went bad.

Double check your connectors for the power switch to make sure its on properly.

If there is a computer shop near you you can call them and ask if they have the tools to test a PSU. If so I would suggest that because it would probably be the fastest way.
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January 25, 2011 12:35:21 AM

jimmysmitty said:
Well it almost sounds like a bad PSU but those OCZs are not bad. They shouldn't die off tht fast. But to test if it is the PSU, I would suggest removing everything from the mobo except the CPU and one stick of memory. Then try booting it up.

If it boots it can show that the PSU isn't able to supply the needed watts. If it doesn't boot it can still mean PSU but it could also mean the mobo went bad or something else major went bad.

Double check your connectors for the power switch to make sure its on properly.

If there is a computer shop near you you can call them and ask if they have the tools to test a PSU. If so I would suggest that because it would probably be the fastest way.


Thanks jimmysmitty

It tried exactly as u have suggested and still the led keeps blinking....
I even removed all the wires( data and power) except MOBO power ( just 20 pin connector and still same.....

Wondering what is faint(tick) sound ...

How do i determine if the MOBO is bad...
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Related resources
a c 126 à CPUs
January 25, 2011 1:29:27 AM

I have never heard a tick sound from a computer with just the power to the mobo. I wonder if it could be a fried capacitor.... but that mobo uses all solid state capacitors and I have yet to see one blow but I guess some people have:



I would check the capacitors on your mobos. If any look like that then that might be the mobo. If anything the ticking sound could be from the PSU.

http://www.tomshardware.com/forum/264358-28-power-suppl...

Thats a interesting thread. The guy had a clicking sound that was coming from the PSU but it was due to a bad mobo that probably had bad voltage regulators or caps.
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January 26, 2011 5:10:50 PM

Keeping my ear close to the PSU, I am sure that the PSU is making the faint tick sound.
Does that mean the PSU is bad or the mobo.

I have a 8 yrs old Sony PC. Can I use its PSU to try boot MOBO/CPU or do u guys think voltage ratings/connector might have changed.
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a b à CPUs
January 27, 2011 12:15:40 AM

TRY THIS, It's a PSU test, but only a basic test to see if it powers up and stays on.
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a c 172 à CPUs
January 27, 2011 4:10:27 PM

Work systematically through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If not, continue.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different, but they all use a single short beep for a successful POST.

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

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

Make sure you plug the CPU power cable in. The system will not boot without it.

I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case once you are finished.

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.

If no beeps:
Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.

Silence, long single beeps, or series of short beeps indicate a problem with the memory. If you get short beeps verify that the memory is in the appropriate motherboard slots.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.
At this point, if the system doesn't work, it's either the video card or an inadequate PSU. Or rarely - the motherboard's PCIe interface.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
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February 7, 2011 1:19:51 AM

Thanks guys for all the input.. You guys ROCK
Took the PSU to my friends and his Mobo had the sae blinking LED
I was able to borrow his psu and my Mobo booted fine....

Wouldn't recommend OCZ...this is too short time for a PSU to die...
My SonyVAIO PSU is still good after 10 yrs.

I have to pay shipping too.....and have not yet received the MIR.RRR
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