What is wrecking my mobo's?

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Thickbrit

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Hi all,my 1st post here,and i desperately need your help with an expensive problem i'm having.I normally run a IC7max3,2.8c,antec tc550 & a mach2.I have had 3 max3's(at £150+ each) die on me since january.All 3 had exactly the same problem.Something is blowing the little capacitors on the rear of the cpu socket on the back of motherboard(inside the chamber with heating element in it).The last max3 i got on friday,installed it,double sealing all mach2 joints,played bf1942 for 5 hours straight,shut down for 30 minutes,went to restart,totally dead !!I was so so gutted, it took me till now to order a new max3+3.2c.If it destroys my new stuff again,i think i'll end up either suicidal or homicidal.Seriously though,i'd appreciate any help you can offer.My thoughts so far are:condensation?(not likely,my sealing is manic):could that heating element be faulty?(could it fry cap's):is it vital to hook up usb & install software?(cos i dont normally):faulty psu?(unlikely,new+volts are fine with multimeter):Faulty mach2?(seems all fine,idle-55/60c,load-40/45c,cpu-10/15c).Sorry for the long post but believe me ,the full story is a lot longer.
 
i know this sounds stupid but the back of the moterboard isnt making contact with anything conductive is it? i blew up a mobo in a cheap case before because the case came with the screw things for the motherobard in place and i didnt check they all lined up with my mobo, so wen i used it there must of been contact with something which shorted my board and amanged my CPU too :(
 
first of all check EVERYTHING on the mobo chassis to see if a standoff or something else is shorting the mobo.

if not then i would say its condensation...

i dont know why but i had codensation probs with both my P4C800E

One of them died...the new one still had some probs again...Seal string everywhere and stuff...
 
ThickBrit

Welcome ! Between being a comic and asleep, I'm an Electronics Engineer. Don't suppose youve got a piccie of the caps in question, or could clip one off the web to show exactly which ones? What d'ya mean blow - like bang - and there it was gone? What case R U using?

I'm also interested cos I've got same mobo and will be using Mach II GT. Are you buying a new board each time as well ? If so more like rich brit!

sw
 
Get some Dielectric grease and cover the area on the back in a thick layer.

Try to keep it away from the seal string though as it soon removes its stickyness.

This is what I did:

Posted by Russell_hq on xtremesystems:

'You can get this from http://www.farnell.co.uk

3821407 PLASTIC COAT SPRAY 200ML Volume 200 ml £3.55

537019 SILICONE COMPOUND 100G DOW CORNING (DC4) £3.60

3821456 COLDKLENE DEGREASER 200ML Volume 200 ml

You get a clear waterproof coating for the PCB, a dielectric grease for the socket and a cleaner (recommend for removal of clear coating)

The beauty of this is you get everything you need to condensation-proof the board and socket, farnell has a minumum order for credit cards, £10 before VAT, and this comes to £10.11 (took me a while to find the products that would take me to 10 quid) and then you get free delivery. Total cost £11.88'
 
Talk about damn impressive response guys, keep up the good work. Like Standin Wave suggests, get a pic for us to have a look at. I'm sure between us we can all help out. Good luck with your new mobo, and thanks for posting. :)
 
Thanks for all the suggestions guys,im fairly certain it isn't shorting on the case or standoffs though,also wrecked board#3 had dc4 generously smeared around all the components & away from sealstring.On #3 i also put sealstring all round the outside of the3 joints(like puttying a window).I would post up some pics, but they aren't very clear.The components i'm talking about are immediately behind the cpu socket on rear of mobo,labelled mc471 to mc482,and by blowing ,i mean they smell burnt,there is like a light brown/white deposit on and around the solder joints,and if you touch them,they fall off(pads & all sometimes).Lets suppose it is airtight,what else could do this ?.Is the usb & software vital ?
 
o.k. heres some pics, pic 1 shows the area on rear of motherboard i'm talking about.Pic 2 shows blown components still intact, pic 3 shows the components after they came away taking the pads with them(arrowed).Unfortunately i'd already cleaned up the deposits i mentioned earlier.Btw, i know my digicam is rubbish.
 
this is a completely wildshot mate as i dont know, but have u been using the same PSU for all the mobos? maybe the conector from the PSU thats going to the board is faulty?
 
photos

TB - d'ya win that digicam from Phil in one of his generous competitions? The photos are a bit too close to tell where the caps are - so as the Canaries are promoted, I got my mobo out of its wrapping. The caps on my board are on the back. You dont reckon the weight of the phase change head is flexing the PC board and causing the thing to twist and touch the case? Another cause could be if most of the PCB is warmish and the CPU is very cold again differential expansion could cause it to bend. The dielectric grease could easily be 'punctured' by the pressure of the board. Try double sided taping some thin PTFE sheet to the metalwork underneath the mobo. I've seen enough product I've worked on over 20 years being returned from a Mil environment to have a wild imagination about failure modes

sw
 
Singular.

of course.

On a more serious note I will be launching a comp soon, where I'll be giving away a lovely new Coolermaster case, worth over £100 :eek:
 
Phil Stanbridge said:
Singular.

of course.

On a more serious note I will be launching a comp soon, where I'll be giving away a lovely new Coolermaster case, worth over £100 :eek:

can i have the question in PM so that i can start looking from now :D....
 
name='Phil Stanbridge' said:
On a more serious note I will be launching a comp soon, where I'll be giving away a lovely new Coolermaster case, worth over £100 .

Hope the holes are in the write place ! (Whats makes me think I'm not gonna win ??:( )

sw
 
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