PC with replacement mobo doesn't boot

[AlFrugal]

This September my PC (built in February 2011) failed to boot. The symptoms (e.g. CPU fan not spinning, even with a substitute PSU) led me to suspect a failed motherboard. I received and installed a replacement motherboard on October 7.

Symptoms at power-up (with replacement motherboard):

1. One short beep (I believe this means successful POST)

2. Screen remains dark; screen power indicator remains yellow ("no signal")

3. Keyboard LEDs remain dark (no customary startup blink)

4. CPU fan IS spinning

I don't believe the mobo is shorting to the case. The case has nine preformed standoffs. These line up with the nine mobo mounting holes.

I possibly damaged the CPU when transferring it to the new mobo, in the process of removing the stock heatsink. (The CPU seemed to mount OK on the new mobo). Also, when reinstalling the heat sink I had to reverse its orientation after I had applied thermal grease to the CPU and had pressed the heatsink onto the CPU.

Recommendations on what I should do??

CPU: AMD Phenom II x2 (stock cooler)
Memory: 2 x 4GB Corsair XMS3 DDR3 1333
Original mobo: Biostar TA890FXE
Replacement mobo: Gigabyte GA-970A-UD3
Graphics: EVGA 512MB GeForce 210
PSU: Antec Neo ECO 520c (520W)
Case: Thermaltake SViking VA4000BWS

 

[Ketchup]

Curious as to what prompted the reverse orientation of the fan. Was the CPU mounted in a different direction?

Have you tried booting one stick of RAM at a time?

 

[AlFrugal]

Wrong fan orientation is because I haven't figured out the AMD socket. There are mounting lugs on two opposite sides of the socket and they look identical to me. Thus, I thought that I had two choices of orientation in mounting the fan. I picked the one with the easier connection of the fan wire to the mobo fan header. When I tried to depress the fan mounting lever it would not budge. When I reversed the orientation, I was able to depress the mounting lever.

I guess I need to rerun the one RAM stick at a time test. I did run it, but at that time there was an extra brass standoff in the case (left over from the previous mobo) which was possibly shorting the mobo. (I have since removed that standoff.

 

[Ketchup]

OK, let us know how it goes.

Several years ago when replacing a motherboard for a customer, the CPU pulled out of the locked socket with the heatsink. After straightening out some pins, the CPU was fine, but talk about nerve-racking!

 

[AlFrugal]

I reran the test booting one RAM stick at a time (eight tests. Each of two sticks in each of four sockets). Still no video or keyboard-LED blinks.

I read the article from PCSTATS.com "Beginners Guide: How to Install/Remove AMD Socket AM3 CPU and Heatsink". I removed the CPU to check for possible bent pins. I saw no signs of damage.

At this point my prime suspect is the motherboard. Are there additional tests I should do? Should I contact Gigabyte and/or Newegg?

 

[monkeydelmagico]

It's a bummer neither board has onboard graphics. Don't suppose you have a spare GPU around?

 

[Ketchup]

Which model Phenom II do you have?

 

[AlFrugal]

monkeydelmagico: I don't have another PCI-e graphics card. But the fact that the keyboard LEDs don't blink on power-up leads me to think that the problem is more serious than a failed graphics card. Also, the graphics card was working fine with the original mobo.

ketchup79: Phenom II x2 555 Black Edition 3.2 GHz

 

[denis280]

(e.g. CPU fan not spinning, even with a substitute PSU)

What about if you try with the new Mobo.