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Hi! I've just assembled a computer, and it's not starting up properly. I followed the advice from the sticky thread about troubleshooting from 'bare bones.'

AMD Phenom II X6 1055T Thuban 2.8GHz Socket AM3 125W Six-Core Desktop Processor
GIGABYTE GA-880GM-UD2H AM3 AMD 880G HDMI Micro ATX AMD Motherboard
CORSAIR XMS3 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666)
CORSAIR CMPSU-650TX 650W ATX12V / EPS12V Power Supply

PLEXTOR 24X DVD/CD Writer Black SATA Model PX-880SA-26
WESTERN DIGITAL CAVIAR SE 250GB WD2500AAJS HDD

Even with only the PSU (24-pin and 12V 8-pin), fans, CPU, RAM, and front panel connectors connected to the motherboard, I get no monitor signal. The lights on the keyboard do not light up, which I think means the motherboard is still not getting power, or is dead. I presume it's not POSTing, as I hear no beeps. All computers still beep, right? It's been a while since I did this.

The fans are spinning, power LED is on, and when connected to the PSU, the DVD and HD drives are powered properly.

I've checked and rechecked cable connections, reseated the CPU, and tried using both sticks of RAM and each alone. What else can I do?

Thanks in advance.

Edited by ithryn because: n/a
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Dani AI

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Good troubleshooting so far, — the fact that the keyboard LEDs light on PSU standby but behave differently when you try to start is a very useful clue. Because you’ve already reseated the CPU and tested memory sticks, focus next on the PSU/motherboard interaction and anything that can cause the PSU to go into protection.

Try these steps in order:

  1. Connect a small PC speaker to the motherboard speaker header (if you don’t have one, get one or borrow). With the speaker attached, remove all RAM and try to start; a working BIOS normally gives a distinctive “no RAM” beep.
  2. Clear CMOS (jumper or remove battery for a few minutes) and then try one stick of RAM in the manufacturer’s recommended slot.
  3. Test outside the case (breadboard): place the board on cardboard, attach only CPU+cooler, one RAM stick, PSU 24-pin and CPU 8-pin, speaker, and short the front-panel power pins with a screwdriver. This rules out a standoff or case short.
  4. Swap the PSU if possible. A PSU can provide 5VSB for peripherals but still fail under load. If you must test the PSU in isolation, don’t rely on a paperclip test alone — it doesn’t prove the PSU works under CPU/motherboard load.
  5. Inspect the CPU and socket closely for bent/missing pins (AMD PGA CPUs have pins on the CPU) and check that the CPU power connector is fully seated (the 4+4/8-pin EPS).
  6. Verify monitor/cable and try the motherboard video output or a spare video card — sometimes a missing video source looks like “no POST.”

If you still get no POST beeps with a speaker attached and a known-good PSU, the most likely culprits are the motherboard (short/failed VRM) or a faulty CPU. Handle components carefully and avoid powering repeatedly if you suspect a short; at that point test RMA options or local bench diagnostic service.

Member Avatar for ithryn

Correction to the above, as I can't edit it after 30 minutes:

The lights on the keyboard do light up when I flip the PSU from O to I, but they do not light up once I power the computer on, which makes me wonder if the motherboard is still not getting power, or is dead.

Member Avatar for ithryn

Could it be a problem of the small wires from the front panel not being all connected correctly? They're powering something on, at least - PSU, fans, drives, case LEDs.

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