Asus M3A78-T no POST

[mofta]

I'm putting together a new system and cannot get it to POST.
It's been about 2 years since I built the last one, but I'm pretty sure I've put it together correctly.

Here's the parts.

ASUS M3A78-T
Phenom 8750 2.4GHz
OCZ Reaper (PC2 6400) 2x2GB
XIGMATEK HDT-S1283
CORSAIR CMPSU-650TX 650W

I've connected the 24pin and 4pin PWR to the MB.
I've connected the front PWR/RESET/Speaker ..etc.
I've connected the Chasis Fan and CPU Fan
I'm using the onboard VGA

Everything else is disconnected to eliminate it as a source of the problem.

After putting everything together and attaching the Power supply cord, the MB LED is ON.
When I press the PWR switch, the power supply fan and chasis fan starts to turn.
But, the CPU fan does not turn and there are no beeps or front LED lights.

Here's what I've tried to isolate the source.

Power Supply (Not Likely)
I've connected the new PWR Supply onto my old MB and it boots up.
I've also connected the old PWR Supply onto the new MB and it does not.


Memory (Not Likely)
I've tried different configurations of 1 or 2 sticks in different slots with the same results.
My previous board did not use DDR2, so I couldn't try it out. I think it's unlikely both sticks would have an issue. Also, I think it would still give some Beep Code or something even without memory.

Video (Not Likely)
I've used my other PCI video card and still no display. Also, I would still expect beeps without video.

So it's likely the MB or the CPU, but I do not have any spare parts to determine which one is bad. Here's some observations.

1) The CPU fan works on my other MB and the supply pin on the MB is at 5V. The other 2 pins also have PWR, but not 5V. I'm guessing there is some signal not being sent to start the fan. What condition would do this?

2) If I take off the heat sink and touch the CPU. It will get hot after about 30secs.

3) There was a small amount of thermal past that oozed off the top and could have touch the pins. I don't think thermal past is electrically conductive, but I removed the CPU from the sockets and wiped it off. I also inspected the pins and they all look OK.

4) There is no smoke or burnt smell.

Any ideas or other tests I can try?

 

[rdb]

I believe that you have a wiring problem. But I would also make sure that the standoffs are right and that nothing is touching that might short it. Unplug everything and reinstall. I didnt see anything about the HD. Did you move a old HD with OS and hope it would boot? Wiring or short the most likey though. CPu fan pluged in to the right place on the MB?

 

[Guest]

Hi there mofta,
I'm having the same problem with my SECOND ASUS M3A78-T MoBo. The first one had the exact same problem. The only difference from your situation is that I get the CPU fan to spin.

I have also tried the DVI port with same result.

Unfortunately I'm not able to get any support from Asus or the retailer. They accepted my complaint about the first one, though. But I'm not too eager to do the same round trip again, just to get the same result...

Have you had any breakthrougs in your debugging?

 

[mofta]

Unfortunately No.

Asus, told me to upgrade the BIOS, which did not work.
Finally I had to take it to a repair shop. They told me the CPU is working, so I have returned the MOBO.

I'll let you know if I see any better results with the 2nd one.

 

[neurodarcy]

Hi there,

I don't know if you will read this at this point, but I found this thread after I just recently purchased my M3A78-T Mobo and had the exact same problem as mofta, all fans spinning, LED on, front panel LEDs working, but no POST and monitor shutoff.

I did end up fixing the problem with help from ASUS actually, and it turned out to be the RAM itself. I was using compatible Corsair Dominator 1066 DDR2 sticks but apparently RAM sticks with heat spreaders require the BIOS to be set manually to recognize the RAM stick's settings (2.1V, 1066MHZ, 5-5-5-15 latency paramaters in my case)

Once I booted up with only 1 stick in the first slot, I got the Mobo to POST and enter BIOS to change these settings. You need to set the AI Overclocking in Advanced to Manual and then enter the values in for the RAM stick for each of the paramaters above.)

After a reboot and POST, I shut down, added the other sticks (3 1GB sticks for XP, doesnt recognize the 4th. Going to install Vista 64 to get use out of my 4th GB), and the BIOS registered them fine.

I hope this helps if you are still having troubles with this board as I've seen numerous posts on newegg and the like about DOA boards and no POST boards. It may just be that the system is not set up correctly and the board is fine.

Now I need to upgrade my DVD drive and monitor and I'm good to go. ATAPI drives will not work with this board (found that out yesterday!)

Good luck!

 

[COSkier1]

Nuero-
so you got it to initially POST using only 1 stick of RAM?
I've been having the same issue with a similar mobo, just the -EM model, but I've not been able to get POST with any config of RAM that I have.

Mofta- have you found your solution yet?