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ASUS M4A78LT-M LE will not boot (pos power problem?)


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#1 chow34

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Posted 05 July 2014 - 10:09 AM

Hi,

 

I purchased the above mobo with an Athlon II x2 250 3GhZ processor (don't laugh) to upgrade my old system. Unfortunately I can't get it to work, it does not POST, no power to USB or PS2 and no display (have tried on board ATI Readon 3000 and a PCI card. The power light does come on and the CPU fan turns.

 

Have tried all the usual troubleshooting techniques. Just power + panel, no ram outside case etc.  

 

I've read that power may be an issue, and my PSU (400W) does seem underpowered, producing only 12A at +12V. The spec required are 15A at +12V. 

 

i just wanted to check whether it's worth upgrading the PSU before I send the mobo back, or whether the symptoms described wouldn't be caused by an underpowered PSU?

 

Also, I was wondering if it's possible to supply too much power? I'm looking at a 500W PSU replacement, that claims to produce 30A at +12V. Would this be an issue if the 12V rail only required 15A?


Edited by hamluis, 15 July 2014 - 03:27 PM.
Moved from Internal Hardware to System Building - Hamluis.


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#2 JohnC_21

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Posted 05 July 2014 - 10:23 AM

There are other people here with better hardware experience but no, you cannot have a PSU that is too big. It will only provide what the motherboard and cards will draw.

 

Did you attach the 4pin CPU cable to the motherboard?

 

Here is an excellent troubleshooting guide for a no-post issue. You have probably done most of these steps but there may be something you overlooked in the guide.



#3 chow34

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Posted 05 July 2014 - 10:27 AM

@JohnC_21

 

Thanks for response, will take a look at guide. I attached the 20+4 connector correctly. Power comes on so the pin connectors were attached properly.



#4 JohnC_21

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Posted 05 July 2014 - 10:37 AM

I did not mean the 20 + 4 pin. I was talking about the 4 pin connector near the CPU on the motherboard. I am sure you attached that, correct? The PSU should have a 4 pin connector name CPU.

 

connectATX12Vpower.jpg


Edited by JohnC_21, 05 July 2014 - 10:38 AM.


#5 chow34

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Posted 05 July 2014 - 10:39 AM

Sorry, yes I connected that also.

#6 JohnC_21

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Posted 05 July 2014 - 10:43 AM

okay, then I would follow the steps in the guide. Hopefully the other people with more hardware experience will have other ideas. If you do not get any other responses PM a moderator and have the thread moved to the System Building Forum.

 

Edit: you can go the ASUS website and get the supported CPU and Ram module lists.


Edited by JohnC_21, 05 July 2014 - 10:45 AM.


#7 chow34

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Posted 09 July 2014 - 05:39 PM

I tried a band new Cooler Master 500W PSU with 20A at +12V with no joy. Sent it back, vendor said it works fine for them and can provide evidence. Really not sure what could be wrong, I've built PCs several times before with no problems. 



#8 hamluis

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Posted 09 July 2014 - 06:13 PM

FWIW:  I have the M5A78L-M board...I would disassemble/reassemble from the beginning.  It should be working.

 

What RAM are you using?

 

Re PSU...I can run mine with 500, 550, and 600W PSUs with no problems.

 

Is this a brand new board...or is it something purchased used?

 

Louis


Edited by hamluis, 09 July 2014 - 06:16 PM.


#9 chow34

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Posted 15 July 2014 - 02:42 PM

I got Kingston 1333 DDR3 2GB. Kingston RAM appears on the approved RAM providers list. I have tried the motherboard with and without RAM.

 

The boars is used, from a PC recycling organisation.

 

Since I last posted, I had returned the board, they have tested and have stated emphatically that it works and have since returned back to me.

 

Yet despite using a 500W PSU which should be more than adequate, I still cannot get the board to post, or power USB mouth/keyboard. 



#10 JohnC_21

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Posted 15 July 2014 - 03:17 PM

Have you tried attaching your devices to the motherboard outside the case and seeing if it posts? Maybe there is a short somewhere between the motherboard and case. I think you would get better responses to your problem in the System Building Forum.

 

 

Moved topic to System Building forum - Hamluis.


Edited by hamluis, 15 July 2014 - 03:28 PM.


#11 chow34

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Posted 15 July 2014 - 04:28 PM

@JognC_21 have tried outside case. 

 

The company is emphatic the board and CPU works. I tried looking for a more powerful PSU in Maplin today but was told 500W should be more than enough, even for more modern systems. 

 

The specs of my PSU are 500W (total) +3.3V 22A, +5 20A, +12 20A, +5.5SB 2.5A. The guy at Maplin was convinced this should be more than adequate and advice me not to bother buying yet another PSU.



#12 dikbozo

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Posted 15 July 2014 - 04:30 PM

I recently did something like this and had to be a very careful tyke in unbending the bent pins on the CPU. Make sure the CPU is correctly oriented when inserting ti as you can easily bend a pin or two and that is all it takes.

 

A second thing you might consider is the health of the CPU. A bad chip is a bad a bad board.

 

You have conclusively proven it isn't a PSU issue. I have one of these running happily(?) in my local server for about 3 years now. The PSU there is an old 350W that just keeps on humming.



#13 chow34

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Posted 15 July 2014 - 04:44 PM

The CPU was pre-attached, as it came as a bundle. I have double checked the CPU though, all seems fine.



#14 JohnC_21

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Posted 15 July 2014 - 04:56 PM

I would make the people who sold you the board ship you a new CPU with exchange.

 

This person had the same board, same problem, no bent pins on the CPU, but in the end it was a bad CPU.

 

Edit: I am no hardware expert but if you can rule out the PSU, CPU, and motherboard, The only thing left is the case. Is it possible the wires to the Power Button are bad? Did you use the power button to turn on the motherboard or did you short the jumper pins on the board? If the power button is somehow shorted, it would be like booting and then holding down the button to cause a shutdown. Just throwing out some ideas.


Edited by JohnC_21, 15 July 2014 - 05:32 PM.


#15 jonuk76

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Posted 15 July 2014 - 08:52 PM

Have you tried resetting the CMOS?  Unplug the system and move the CLR RTC jumper to pins 2-3 for 10 seconds or so, and put it back to its original position.  It sometimes helps with systems that won't power up.

 

If you powered it up outside the case with minimal components attached (no drives, no add on cards) that rules out things like the case shorting out the board.  It'll never complete POST without RAM of course.

 

Also I hate to say it, but I don't think that sounds like a very good PSU.  The amps you've quoted don't even add up to 500w, and 240w/20A on the +12v rail on a modern "500 watt" PSU is dodgy.  High quality 300 watt PSU's can supply more than that at 12v these days.  Unless perhaps there is more than one 12v rail, which is quite common, but they should give a combined 12v rating across the two rails.


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