Built new desktop last night. PC won't post at all

October 17, 2014 6:43 AM

Built my first desktop last night completely on my own. A friend has helped in the past but this was my first solo experience. It was much easier than I anticipated. However that's where the easy part ended :L

I can't get the system to post at all. It turns on, the liquid cooling works and the fans spin, as does the case fan. After about 15-20 seconds it reboots in a loop. Nothing on the screen no sound. The only light up is the power button on front, I don't get lights from the HDD activity, no response from reset button. I've done the following troubleshooting so far:

* Cleared the CMOS (by jumper and removed battery for 10 mins)
* Checked all connections to make sure they're seated properly
* Removed all RAM sticks to see if I could get even a no memory post
* Taken the video card out and tried with simply the onboard mobo graphics
* Checked CPU, the included thermal paste on the Corsair H100i was shoddy so I rubbing alcohol removed and reapplied good Arctic Silver thermal paste
* Checked all front panel connections on the mobo. They're as the manual says. (All the labels are facing one direction etc) It powers on just fine from the front button.
* All components are brand new.
* Even unscrewed the mobo from the case and put it on a box to ensure there was no case short happening anywhere.
* Shouldn't be the PSU because it's 650w and it powered everything on ok...

Last step I might breadbox the thing tonight or over the weekend. What else can I check? Really frustrated. I'm pretty sure I hooked everything up correctly.

Here's the full build part list.

posted by PetiePal to Technology (20 answers total)

You have the PC speaker connected, and it's not beeping? If you've removed *all* peripherals and all RAM, it should at least give you a failed POST with a beep series (I think 3 beeps indicates a memory error). One more thing you might try if you haven't already would be to remove any KB and mouse you have attached and give it another attempt to boot; I've had a couple cases in the past where a flaky USB keyboard has caused very odd behavior at boot time.

Failing that, I think you've done a comprehensive job of troubleshooting. I can't really think of much I'd look at short of trying another CPU, and then another motherboard. :( (But it's been a long time since I was a screwdriver jockey and I've only built and tweaked my own personal machines for a fair number of years, so I don't have full exposure to modern failure conditions.)
posted by jammer at 6:58 AM on October 17, 2014

Rubbing alcohol? Not so sure about that...

Did you try the simplest, barest configuration (i.e. no ram AND no video card, - not individually testing things, trying it all at once)?
posted by devnull at 6:59 AM on October 17, 2014

If the machine doesn't post breadboxed (IE just with the MB/CPU/RAM/PSU and using a screwdriver to short the power button jumper), it is very, very likely to be an issue with either the motherboard or the power supply. If you have a multimeter you could check the rails on the power supply to see if it is working, failing that you could use a paper clip (google this) to see if the PSU will at least run continuously.

Did you check the LGA socket to see if there were any bent pins (use a magnifying glass for this)? The socket was designed by sadists and is easy to damage.

Unfortunately you are going to probably have to return a component at some point and hope for the best. I would go with the MB; it's much more likely that something from ASrock is busted than something from Intel, and there's much more that could go wrong.

I had this same issue earlier this year (eerily similar) and it turned out to be the MB.

I might also switch MB brands. ASrock... ech.

PS. Rubbing alcohol is fine to remove thermal paste as long as it stays on the top (heat spreader) of the CPU. Don't worry about that.
posted by selfnoise at 7:05 AM on October 17, 2014

Disconnect the case power button and related connections from the prongs on the motherboard (I know it's a bit of a bitch to redo all those small connections while it's inside the case) and start it up with a key or a screwdriver, just tap the two prongs responsible for power key. Take the case out of the equation.

I'll also second jammer: remove any and all USB devices.

Based on what you've told us, though, you've got a bad motherboard. I don't think you need to try another CPU first; I think you should RMA the motherboard at once.
posted by Sunburnt at 7:07 AM on October 17, 2014 [1 favorite]

Last time I built a PC (it's a less than once a decade thing for me, so I'm far from an expert), I had some initial difficulty with getting the psu hooked up right. Back in my day, the psu had one plug that went into the motherboard, and (afaik), they were all the same. This new one came with some weird connector where you could split off part of it if necessary. I don't recall the specifics of it, but I know that I initially got it wrong and nothing worked. I know I'm showing the extent of my ignorance here (the only PCs I usually deal with these days are servers built by someone else and nicely racked in a loud datacenter far, far away). But my point is, really carefully check that the psu is hooked up the right way for your motherboard.
posted by primethyme at 7:10 AM on October 17, 2014

Rubbing alcohol? Not so sure about that...

Rubbing alcohol is fine for removing TIM; I've done it plenty of times. The key is to just just enough (less than you think you need), basically just moistening the tip of a Q-Tip. First one will clear a bit off and smear it around a little, second one usually gets the rest, leaving just some streaks. I buff the last bit off with a dry q-tip and it's generally good to go. (I'll usually do one more wet/dry pass after that just to make sure I have a clean surface for the next TIM application.)

I'm more nervous about metal-based TIM and usually go for something non-conductive and non-capacitive. I've never had problems using a conductive TIM, but it always make me more paranoid when I'm putting it on.
posted by jammer at 7:10 AM on October 17, 2014

double check that you have connected ALL of the power connectors. Newer mobos have the big power connector and then a smaller square one that needs to be connected also.
posted by cosmicbandito at 7:21 AM on October 17, 2014 [3 favorites]

Came to say what cosmicbadito said: there are probably two power connectors on the motherboard; they both need to be connected to fully power up.
posted by Benny Andajetz at 7:47 AM on October 17, 2014

We had this exact symptom at work last week - fans and lights but no POST, no video, no beeps - and it was a bad PSU. If you have a spare that's the first thing I'd try, especially since it's relatively easy to swap. You could even test with an old low-wattage one from an existing PC (leaving out the video card) to see if you get anything.
posted by pocams at 8:55 AM on October 17, 2014

I actually went through something very similar to this earlier this year. Are you sure it isn't the monitor, either not hooked into everything it needs to be hooked into (try all possible connections, not just HDMI) or not set to the appropriate display mode (or both)?
posted by koucha at 8:58 AM on October 17, 2014

Newer mobos have the big power connector and then a smaller square one that needs to be connected also.

Yeah, I think that's what happened to me in the issue I described above. The symptom was that it would appear to start to power on in the sense that fans would spin up and stuff, but then nothing.
posted by primethyme at 9:55 AM on October 17, 2014

I'd second checking the PSU. I had similar frustrating issues but replacing that cleared them up.
posted by Carillon at 10:15 AM on October 17, 2014

It's been awhile, but I once had a similar set of symptoms. The culprit turned out to be the Power Supply - it was switched to 240V but I'm in the US using 120V.

So - is there a voltage switch on the PSU?
posted by doctor tough love at 10:32 AM on October 17, 2014

If you are looking at your motherboard as it sits in the case (with the rear outputs to the left), there is a 24-pin connector on the right hand edge. That's the power connector. If it's connected the motherboard will power up and the fans will spin - but the computer won't boot. In the middle of the top edge there is a square 4-pin connector. That's the CPU power connector. Both connectors are needed to boot.
posted by Benny Andajetz at 11:29 AM on October 17, 2014

Response by poster: OP here.

So yes I tried the BASIC most simplest config with only CPU, Cooling unit and NO ram. There is a speaker built into the board I believe, but I've also ordered one of the standalones to plug in.

-PSU is good. Tested in another machine.
-I do have the 24 power connected as well as the 4 pin.
-Not using video card yet was trying on board mobo graphics first. It's set to dvi input, only thing I'm using.
-It's an Intel chip so no pins. And I've reseated it twice, and made sure the thermal paste is good.

* There IS a voltage switch on the PSU but I've made sure it's set right.
posted by PetiePal at 1:19 PM on October 17, 2014

You mounted the motherboard on spacers, right? I have seen motherboard shorted out without them.
posted by Ferrari328 at 2:50 PM on October 17, 2014

Response by poster: Update!

I removed everything from the case and bread boxed it on the motherboard box.

Connected just the 2 mobo, cpu cooling fans, and cooling esata power. Then tried powering on by shooting the power pins. Got a small clock from the psu. Nothing.

Then to go one farther I dragged the case over and connected the power cord from the front panel and got the same thing.

Could this be a faulty psu now? It's an EVGA 750 gold I thought I was getting a good one.

Either way I kinda changed my mind on the motherboard so I have a nice Asus one coming tomorrow... Will try psu with that and if not guess I have to RMA the psu
posted by PetiePal at 2:58 PM on October 17, 2014

Do you have an alternative PSU you could test with?
posted by doctor tough love at 3:10 PM on October 17, 2014

Certainly looks like you've narrowed it down to the motherboard or PSU. My bet is your Asus board will fire right up.
posted by Benny Andajetz at 3:56 PM on October 17, 2014

I'd check the CPU socket for bent pins, and the motherboard website for potential incompatibility with the CPU. I gave up trying to prove it, but the last time I had this problem, I concluded that the BIOS needed to be updated for compatibility, which I couldn't do since it wouldn't even POST. I finally gave up and tried a different combo.
posted by wotsac at 10:44 PM on October 17, 2014