New ITX Build Won't Turn On?

[Twisted4000]

I built my first Mini-ITX computer and, although everything seems to be plugged in correctly, it won't turn on with the power switch. Even when taking the switch cable out of the motherboard and trying to short the pins to get it to turn on, it won't. The green motherboard LED lights up when it's plugged in, but that's about it.

The power supply came with the case (it's an Apex MI-008, and the PSU it comes with is an Allied SL-B250SFX (250W)). I'm assuming it's just DOA? Think I should get a new one or is there something else I can test first? Thanks.

Here are the specs:

Chassis - Apex MI-008
Motherboard - Intel DG45FC
Processor - Intel Core 2 Duo @ 3.0GHz (Dual-Core)
Memory - 2x 4GB (8GB) Dual-Channel DDR2 @ 800MHz
Storage - OCZ VERTEX4 128GB SSD, Seagate Barracuda SATA 1TB HDD @ 7,200rpm
Power Supply - Allied SL-B250SFX (250W)
WiFi - Dual-Band
Optical Drive - HP GH60L SATA DVD Multi-Recorder
SD Card Reader

(Yes I got previous gen parts, this is not a gaming PC and I wanted to save money lol)

 

[Zerileous]

Are these new or used components? Verified functional previously?

The first thing to try in a no-post situation is to remove all of the components not required. So only CPU, cooler, memory, (GPU which is integrated) and PSU. If that doesn't work the next step is to re-socket or install those components, and try a single memory stick at a time. If the system still does not post, then the next step is to remove it from the chassis and try again.

It could be motherboard or PSU, it could also be CPU or memory but I think that's less likely as you'd probably at least have fans spin in those cases. You can try to short the pins on the PSU 24pin header to see if it powers up (be aware that some PSUs don't have their fans spin on idle).

If all of those things fail, I would see if it's possible to test a different PSU. I'm of course suspicious of a 10 year old used motherboard, so I would prefer to verify which part has failed before buying a SFX PSU. That said I'm also suspicious of the PSU bundled with the case.

 

[Twisted4000]

The motherboard, processor and RAM are all used. The sellers I bought them from claimed they were working and functioning properly.

At this point it may not be the PSU because I just tested it out with a different one (only plugged in the 24-pin and the 4-pin, no peripherals or any of the other devices) and same exact response: green LED on the motherboard lights up, but it won't turn on. It not only won't post, but it won't turn on or fans won't spin up period.

Can a non-functioning CPU or RAM really cause the computer to not turn on whatsoever? Not only just not post, but not even power up for a few seconds?

 

[Zerileous]

Most likely the board then, have you tried to take it out of the case? A shorted standoff in the case can also cause this.

 

[EarthDog]

If it isnt that potato for a power supply (get another quality unit sooner than later), it's the board, cpu, or a short. As zerilious said, breadboard it and see if it is a short.

 

[Twisted4000]

Thank you both for your responses. I'll dismantle the thing and test everything out individually and let you know what happens.

 

[Twisted4000]

Problem solved! I took the motherboard out and placed it on a wooden table along with the PSU. Plugged it in and still no luck, so I took out the CPU and re-seated it and bingo, it powered on when I shorted the power button pins. Thank you so much!

 

[trents]

Did you check the bottom of the CPU and the socket for contamination, like leftover thermal paste covering contact areas?

 

[Twisted4000]

Did you check the bottom of the CPU and the socket for contamination, like leftover thermal paste covering contact areas?

I looked at the socket and I didn't see anything. Either I somehow placed the CPU in incorrectly or some dust or something got in between them.

 

[trents]

I was concerned because between the notches on the side of Intel heat spreaders that line up with the socket frame and the retention clamp, it would seem difficult to not get the CPU seated correctly without bending socket contacts. So, I was leaning toward some kind of contamination that was insulating the contacts.