After successfully building and running my 20 bay server for the last few months, a friend asked me to help with their build.  When everything came to me the motherboard and CPU were fitted, but I needed to get everything cabled up etc.

 

Once finished, I plugged the server in, flicked the hard power button on the PSU....and nothing.  That's not strictly true, as the blue fan lights on the Antec 1200 case flashed momentarily, the CPU fan turned slightly, but then everything was dead apart from a green light on the motherboard itself.  I also noticed a slight burning smell, which didn't exactly fill me with confidence.

 

I double checked all of the wiring and it was 100% correct (I even pulled my existing server out of its home and checked the wiring inside that...and they were identical).

 

On further investigation, I pulled the CPU out and found it had several bent pins.  Putting this as the root cause I ordered another CPU, fitted it today and.......exactly the same thing has happened.  A flash of lights, cpu fan turns slightly, the motherboard light is on...but then dead.

 

I'm really scratching my head now, because in my mind the problems can now only be related to the motherboard or the PSU itself.  That said, if it was the PSU I would have thought there'd be NO power at all (remember the green light on the motherboard).

 

Could the initial problem with the CPU pins have fried the motherboard? - and if that's the case, could fitting the new CPU today have fried the new CPU too?

 

Really stumped, so any advice would be appreciated.

 

Thanks

The burning smell (definitely NOT good) makes me suspect the PSU.  Opening the PSU will likely void the warranty, but perhaps you can use a flashlight to peer through the fan grill and see if you can identify any burn marks or other nastiness.  You can also take a good strong whiff of the PSU (again, through the fan grill) and see if you can smell the burn residue.  Either of these should be enough to get an RMA approved.

 

If you hadn't mentioned the burning smell I would have assumed that the RAM was improperly seated.  I've seen 'momentary flash of activity and then silence' type of behavior on my personal server and reseating the RAM solved it.  So you can try that too.

 

I don't think the bent pins on the CPU are enough to really fry anything except the CPU itself, but I could be wrong there.  Just because I've never heard of it happening doesn't mean it can't happen.  By the way, a great way to straighten bent pins is to use the tiny metal tube at the very tip of a mechanical pencil (pic).  Of course if the CPU was damaged in shipping or production then it should just be RMA'd.

 

 

Could the initial problem with the CPU pins have fried the motherboard?

Yes

 

- and if that's the case, could fitting the new CPU today have fried the new CPU too?

Yes

 

About the only thing you can do is start eliminating parts.  Try pulling the RAM and any cards, etc. Leave just the essentials and see if it beeps at you about not having RAM installed.

 

If I had to guess the second CPU might still be good, but the motherboard is probably fried.  You know your PSU works, can you test the board with your PSU?

Thanks for the quick replies

 

tbh I'm not prepared to strip my server to test the PSU in this new one, it's too much work!  Just checked the RAM and it's seated fine.  Shone a torch inside the PSU and no obvious signs of burning, there's a faint smell nothing that I could categorically define as "burning".

 

Sounds to me like the motherboard?

You don't have to take apart your server.  You can take the sides off both server, set them so they are facing one another, and then hook up your PSU to the other server's motherboard, drives, etc.  You then power it on with your server's power button.  I've done this several times, it works fine.  It is also a bit of a pain, but much less so than dismantling your server.

Sense check time:

 

I unplug the main PSU and ATX cables from my server.

I unplug my unRAID thumb drive from my server.

 

I plug the main PSU and ATX cables from the other server into my server, and see if it starts up.

 

That should work shouldn't it?

 

None of my HDDs will spin up, and unRAID won't try to boot, but I'll see if my main server gets any power at all?

 

 

Sounds like the Power Supply.  I saw this exact issue 2 weeks ago on a brand new PS.

I would NEVER power any known good hardware from a suspect power supply.

 

Peter

 

I misread Grumpie's post and made a mistake!  See correction below.

 

 

Sense check time:

 

I unplug the main PSU and ATX cables from my server.

I unplug my unRAID thumb drive from my server.

 

I plug the main PSU and ATX cables from the other server into my server, and see if it starts up.

 

That should work shouldn't it?

 

None of my HDDs will spin up, and unRAID won't try to boot, but I'll see if my main server gets any power at all?

 

 

 

 

That is correct.  Well, that will work at least.    You need to hook up your known good power supply from your server to the other server's motherboard.  Your server's hard drives will spin up since they are still receiving power.  No real need to unplug your flash drive, but it won't hurt either.  The only thing that won't happen in your server is your motherboard and any fans connected to it should stay powered off.  In the other server with the suspect hardware, you should see the motherboard and any fans connected to it power on, but all the drives and other peripherals should remain powered off.  Remember to wear an ESD bracelet or otherwise ground yourself when doing this.  If you don't have an ESD bracelet, make sure to touch both servers with your bare skin before doing anything.  And don't do this while dancing a rumba on a carpeted floor while wearing socks

 

I would NEVER power any known good hardware from a suspect power supply.

 

Peter

 

 

Ditto.

I've experienced what your talking about twice in my life. Once it was a bad power supply and the second time it was a bad motherboard.

 

Smelling something burnt well that would be a HUGE indicator that something isn't right and I would probably chalk that right off the list of good hardware.

Hang on a sec...are people saying NOT to try the iffy power supply with my server?

 

Thinking about it, I can take the power from my unit and plug it into the new server, at least that way I protect my own kit?

Hang on a sec...are people saying NOT to try the iffy power supply with my server?

Yes!!

 

Thinking about it, I can take the power from my unit and plug it into the new server, at least that way I protect my own kit?

Yes, that is what you should have done.

Also, before hooking up your good powersupply to the broken system, disconnect all the non-essential parts (like all the drives) and see if you can get the minimal system to boot.

 

Regards,

 

Stephen

 

Hang on a sec...are people saying NOT to try the iffy power supply with my server?

 

Thinking about it, I can take the power from my unit and plug it into the new server, at least that way I protect my own kit?

 

Shit, I just re-read your post above and realized I misread it the first time.  I apologize if you followed my bad advice.  Here's what you should do:

 

Sense check time:

 

I unplug the main PSU and ATX cables from my server.

 

I plug the main PSU and ATX cables from my server into the other server, and see if it starts up.

 

Hopefully we caught you in time before frying your good motherboard with the iffy power supply.

Too late   Gutted I didn't check for your reply as I thought I'd try it anyway.  Now my main unRAID won't boot and I think I've fried my motherboard 

So sorry to hear that, and I hope the mobo isn't fried.  What symptoms are you seeing?

Sorry couldn't resist 

 

Will try your suggestion over the weekend though to see if I can eliminate the PSU from the equation...will be good if that's the problem as it's a relatively hassle free job

You son of a.... got me good. 

Damn he got me good, I was feeling horrible for him too.

Right folks...I've just switched the power supply from my server into the dodgy one.  No flashes, no burning smell and while the fans naturally aren't spinning (they're still connected to my server), the CPU fan is spinning nicely.  One thing I'm a little confused about though...there's no beep, nothing on the display, which tells me it's not even getting to POST?

 

Also, the reset and power switches do nothing, I physically have to flick the switch on the PSU to shut everything down.  Is this indicative of a fried motherboard?

Seems likely, yes.  The final test is to boot without any RAM installed.  It should start beeping (assuming a speaker is built in or installed).  If it doesn't beep without RAM installed, then chances are it is fried.

One thing to check - that the RAM is the correct speed for the motherboard.  I once had a mobo (two actually) that would not POST, and just started up the fan.  It wasn't until I read the small print again that I found out that the board only accepted 667 or 800MHz RAM and I had been trying it with 533MHz RAM since that's what I had and I knew it to be good.  Took me ages to work it out, but putting the correct RAM in of course fixed it.

Thanks again for the replies, unfortunately it's not the RAM   How unlucky can you be though, CPU knackered (admittedly incorrect install), but motherboard and PSU all fried too