RAM & PSU good but no beep, no POST, no display - Is it the mobo or the CPU?

ambush

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Jan 13, 2002
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When I try to boot a home-built machine, it does not POST and there's no display (even from the onboard VGA video), and when no RAM is installed I get no error beeps (or beeps of any kind).

I followed all the steps of the Tom's guide here: PERFORM THESE STEPS before posting about POST/boot/no video problems!, with the exception of full breadboarding, but there's nothing in the case now except the mobo and CPU anyway.

HARDWARE...
MOBO: ASUS P5G41T-M LX3 (Used)

CPU: Intel Core 2 Quad Q9550 2.83GHz/ 12M /1333 SLB8V LGA 775 (Used)

RAM: 2 x 4GB Micron DDR3 PC3-10600U-09-11-B1, MT16JTF51264AZ-1G4M1. (Used)

CASE & PSU: ROSEWILL R521-M Micro ATX Mini Tower Computer Case with PSU, steel computer case + 400w power supply (New)


Circumstances:
The monitor is connected to the on-board VGA port. The system correctly turns on and off, and some activity from the optical drive is seen while waiting for POST (which never happens).

I used an Antec Digital PC Power Tester to confirm that all outputs from the PSU are in good shape.

I verified that the RAM was good by installing both DIMMS in a different computer, which then worked perfectly. It's still possible, I suppose, that the RAM isn't fully compatible with the mobo...

Under Step 23, it's recommended to uninstall all the RAM and then try to boot and listen for the error beeps, but NO beeps are heard!

SO help me out, please: What steps can I take to determine if the failure is caused by the motherboard or the CPU? If not, what's your opinion on the issue?

Thanks!
 
Solution
CPU failures are quite rare, short of user bending pins on CPU or mainboard, depending on generation...

That leaves mainboard or cpu...

You might consider removing all power, and trying another BIOS battery, typically CR2032 for $3-$4 in many hardware stores...)

Next step is to try a known good PSU of sufficient wattage... (PSU testers typically put no load on the PSU, which really only tells you it powers on and is not a total brick...)

That then leaves the mainboard afterward...assuming the CPU is in fact known good, not bricked by overclocking/overvolting and sold to an unsuspecting buyer on E-Bay......
CPU failures are quite rare, short of user bending pins on CPU or mainboard, depending on generation...

That leaves mainboard or cpu...

You might consider removing all power, and trying another BIOS battery, typically CR2032 for $3-$4 in many hardware stores...)

Next step is to try a known good PSU of sufficient wattage... (PSU testers typically put no load on the PSU, which really only tells you it powers on and is not a total brick...)

That then leaves the mainboard afterward...assuming the CPU is in fact known good, not bricked by overclocking/overvolting and sold to an unsuspecting buyer on E-Bay......
 
Solution