Motherboard doesnt power up when screwed on system case

[suseli]

I have a brand new gigabyte motherboard with intel celeron d 3.0ghz cpu.

I tried to put it in a system case and screwed it, then tried to switch it on,it didnt worked.

I then removed from the case, put it on the table and connected the psu then switched it on, it worked.

I tried replacing 3 diff cases, it doesnt works when fitted to case.

Can anybdy please suggest me what can be the problem. In motherboard case the support screw(metal) are properly fitted.

 

[paparazi]

Possibly one too many bras stand off posts have been fitted so the board is shorting to ground.
Also check the I/O plate to make sure none of the earthing fingers are shorting out the lan or USB connections.

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[wahnula]

Something must be creating an unwanted path to ground or shorting somewhere. Try removing all but 3 or 4 standoffs, leave just enough to keep the board off the case. Do not use ANY rear panel shield yet. If no go, remove those and try only the remaining standoffs.

The only other thoughts I have would be to wiggle the main power supply to the board while switching on or try making a cardboard template to fit behind the mainboard and poke holes in it for the screws, see what happens.

Tony

 

[edfair]

You might try it mounted with just one screw to hold it in place. Then add others between boot attempts.
Trace grounding can happen on the bottom from standoffs in the wrong places and on the top from screwheads overlapping traces.
It is possible you have a bad M/B,with shorted traces, but unlikely with current testing methods.
You may want to verify that the places where the case manufacturer suggests standoffs really are intended for that purpose by the M/B manufacturer. The ground points on the bottom of the board should have a built up area of solder around the mounting hole.


Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[suseli]

The case doesnt requires brass metal standoff. Infact it has got a kind of 6 standoffs which is a part of the case.

 

[edfair]

There are potential problems with embossed standoffs. The surface in contact with the M/B may be large enough to contact a trace. If inspection of the M/B shows a particular grounding pad that might be the source of the problem you can insulate the pad from the standoff.
And if one of the standoffs doesn't have a matching grounding pad you have to use insulation.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[wahnula]

You could also try using insulated washers between the case and the standoffs.

 

[suseli]

I taped the embossed standoffs with the masking tapes. Then put the motherboard n screwed it it, still the same probs.

I think insulated washers a good idea, but is this washers a rubber one or plastic one.

 

[suseli]

where to put insulated washers in embossed standoffs?

I did put that small red circled (kinda washer) between embossed standoffs n motherboard but still didnt worked.

 

[wahnula]

Well I would buy or make some large dime-sized plastic/rubber washers, then get some type of non-permanent cement like rubber cement, then secure them to the case BEFORE placing m/b screws. A coffee can plastic lid comes to mind...I have also seen padded double-stick tape, that might work.

Have you checked that m/b with a fine tooth comb for cracks? Even a minor crack can be death. I would also, while testing outside the case, string a jumper from board ground to case ground to see if it causes the problem. There may be a short or ground loop somewhere. Yes I know the ground wire from the PSU goes to the m/b just humor me please!

Tony

 

[edfair]

If tape didn't fix it then time to look for other problems. Pull the board and remove the I/O plate then reinstall the board and see if it works that way.
Look for possible ground issues with screw heads.
Possibly put the board in with only one screw, then add others, one at a time.
I've used plastic electrical tape for insulation. Doubled over to give extra thickness but was careful not to tighten the screws too tight because the tape plastic flows under pressure and you'll end up with a ground.

Ed Fair
Give the wrong symptoms, get the wrong solutions.