Where could my chassis be causing a short?

gizmo1990 · 5 Apr 2011 at 22:48

I'm trying to install a new board in my case, a sff sg05. I've had the motherboard working on the box and been installing the os.

However, I've just put the board in the chassis (and boy was it a utter utter git!!) turned it on and... nothing. Psu wouldnt come on at all. Fearing the worst my heart sank and I took the board out tried it again and thank goodness it worked.

So I've a dilemma, why wasn't it working in the chassis? It's already be stripped and blown with canned air. It looks fine. Could it be causing a short somewhere? Does anyone have any suggestions for tracking the problem down?

Could really do with some advice.

Kaeo · 5 Apr 2011 at 22:56

Are you installing it into a case with a sliding Mobo panel, or the old fashioned way?

Also, anything electrically charged can cause shorting, but it's most likely to be screws/standoffs.

http://forums.overclockers.co.uk/showthread.php?t=18046396

Double check everything before you power up. Remember, that first button press can give life (or sudden death).

Baldbloke · 5 Apr 2011 at 23:00

Check that there isn't one too many standoffs on the case. Possibly one that's not being utilised by your new motherboard could be causing a short.

Are you sure it was a short and not a loose connector?

Surveyor · 5 Apr 2011 at 23:13

Baldbloke said:
Check that there isn't one too many standoffs on the case. Possibly one that's not being utilised by your new motherboard could be causing a short.

And are you actually using the brass standoffs?

gizmo1990 · 5 Apr 2011 at 23:15

Thanks for the replies guys.

The board fits the old fashioned way and it was a pig getting it under and slotted into, the io panel.

There's only 4 stand offs. Basically I can't see anywhere inside the chassis that could be causing a short. Same with the screws.

All the cables seem fine as it works out of the chassis.

I just can't understand what could be causing the short!?

gizmo1990 · 5 Apr 2011 at 23:18

Surveyor said:
And are you actually using the brass standoffs?

I'm using the stand-offs built into the chassis

Baldbloke · 5 Apr 2011 at 23:22

4 standoffs? That seems far too few. My mobos use 9. If it is a short that's causing the problem then it may be the mobo is touching the case due to flexing. E.g. Too few standoffs.

Surveyor · 5 Apr 2011 at 23:35

What size of motherboard is it?

ATX uses 9 screws.

MicroATX uses 6 screws.

gizmo1990 · 6 Apr 2011 at 00:04

It's mini-itx so for screws only.

I wonder if the mounting screws could be the problem? Should they be a certain type? Of made of a certain metal?

Baldbloke · 6 Apr 2011 at 00:12

The motherboard is/should be insulated around the screw holes such that, correctly aligned, no short should occur. Usually brass but doesn't matter.

Have you inserted the board in to the case only once? Are you certain the power pins were correctly wired when it was in there?

You seem certain it's a short. I'm not so sure. You would usually get some other indication if it were a short (but not always) such as heating, burning smell, sizzling sound. None of these are nice to witness. Other symptoms of a short include partial power up, dimmed lights, short period of operation then stops. The symptom you describe could be a short too. It's just too easy to overlook a misplaced connector or wire.

Hydrogoo · 6 Apr 2011 at 08:57

Is there also a 4 pin connector for your motherboard as well as the 20/24 pin connector? Usually near the CPU socket. If you haven't plugged htis is it could cause the non booting issue that you are having.

Oh, another school boy error that may be causing it... Is there a rocker switch on the back of the PSU for turning it off and on again? Make sure thats set to on!

davieg · 6 Apr 2011 at 12:20

Also check if the IO shield little springy things around the port (thats as technical as get with them

) are lined up and sitting correctly and not missing and shorting something out.

Dave.