Bizaare random PC shutdown only when connected to chasis

[wuk]

Hey,

Firstly thankyou very much for taking the time to read and I appreciate any input. sorry for the lengthy post but this is the most insane PC hardware problem i have ever encountered and also the first time i havent been able to diagnose & resolve a system by myself with the help of other IT savvy friends and googling forum-posts on such wonderful sites as this one!

f you like challenge then please give me some feedback i will be sooo grateful for any suggestions.

I have been struggling with my friends system for 3 days now. I'll be as brief as I can.

The board is an asrock n68 vs3 ucc.
(have replaced the mb with same type once already)
have tried 2 new PSU since first having a problem on this PC as you will see below.
current chip is amd phenom x2 255 3.1Ghz
and have also tested with amd phenom x6
have used different RAM (1 stick at a time in each of 2 slots)
there are no expansion cards in this system at all.
The system is not overheating i have rigorously checked for this.

The system is only 4 months old.

NB i am in australia and the weather has recently become hot.

The first time a problem appeared was a few days ago when the system would not turn on. I reseated memory and checked cables etc and a few minutes later it turned on but the problem persisted the next day

So i returned and installed a 550W aerocool PSU thinking this would most likely resolve it.

After installing the replacement PSU the system will power on everytime but would shut down as if the power button had been held in. i have ruled out software as this will occurr in dos xp and 7 (and even a couple of times while i was in BIOS)

i tested diff CPU and RAM but system still crashes.

NB the only slightly suspect thing about this PSU is that the 12V rail shows 12.6 in HW monitor in BIOS but other than that everything is very close to normal.

i tested my phenom x6 in the system but the same error occurred.while this was happening i ran his CPU in my box for 2-3 hours watching a dvd and running a stress-test at max CPU usage with no probs.

so then i tried my PSU which is a good quality seasonic but then i encountered an issue where the system will sometimes not POST or sometimes not display VGA (but would beep at me if i removed the RAM)!?

so i changed the motherboard today for one of the exact same make/model thinking well this has to do it right? but the same problem persisted. the system would shut down randomly (within a few minutes) using the aerocool 550W psu - and the same POST issues occurred as mentioned above when i tried my powersupply.

this left the case as the only possibility. so i took the mb out and benchtested it and the system seemed to run flawlessly. i tried to diagnose the case for a possible short but could not isolate it. it would crash no matter what i did.

while running inside of the case - some of the things i tried are (running only with the ODD and no HDD or running only with HDD and no ODD) swapping power switch with reset switch, checking case visually for anything that could cause a short etc but still the system will shut down within a few minutes of being powered on.

OK so this is where it gets really confusing/distressing - i have put the system in another case i have here but the shutdowns still happen. i have since unplugged the system and currently have it running a stresstest outside of the case and it is running flawlessly.

i'm completely lost for ideas as to what to try next. the only thoought i had was to try gradually reconnecting chassis connectors one by one and seeing which exactly makes it unstable but this seems ridiculous to me so i hoped someone else could give me their opinion.

i am curious about the fact that the system would previously not turn on but since replacing the power supply now it randomly shuts down!

thankyou in advance for any help!

love and peace

will

 

[CaedenV]

rock on! you have got a fun one!
While in the case please try not hooking up the power/reset headers, just use a screw driver or other metal object to short the pins to turn the system on and see if that does the trick.

If not then my bet is that you are having a grounding issue. make sure that the mobo screws are not touching anything they shouldn't. If you are using any sort of old school paper washers to isolate the board then remove them as many boards need that ground. Lastly, use an outlet tester and make sure that your ground is grounding properly.

hope it helps!

 

[wuk]

rock on! you have got a fun one!
While in the case please try not hooking up the power/reset headers, just use a screw driver or other metal object to short the pins to turn the system on and see if that does the trick.

If not then my bet is that you are having a grounding issue. make sure that the mobo screws are not touching anything they shouldn't. If you are using any sort of old school paper washers to isolate the board then remove them as many boards need that ground. Lastly, use an outlet tester and make sure that your ground is grounding properly.

hope it helps!

hey caedenv thanks for your encouragement and suggestion!

i will give that a go because i think i havent actually tried that. i guess the reason i didnt try this is because i thoought the seperate case would already rule that out as being the problem but ill give it a go anyway - at least its a new path to follow.. where it will take me i do not yet know but i shall post back and let you know

thanks again

love and peace

will

 

[wuk]

hey

system seems not to power off while mounted in the case but without any of the headers plugged in. (note that this is the second motherboard, second case and second powersupply lol)

so where do u (or anyone?) think i shoould go from here? oh i should add - im not sure how to go about testing the grounding!

thanks

love and peace

will

 

[jdenova007]

I have seen busted USB ports cause shutdown issues... you only have Keyboard, mouse, and monitor connected right? in the back? Check to make sure you had the front connections connected the right way... having them reversed could cause issues. Maybe you had a 2 part issue.... bad case and bad mobo... or bad mobo and bad PSU....

Weird issue, and I have no other ideas for you sorry.. just thought I would throuw this out there. Plug in the headers one at a time and run tests, should be bale to isolate what connection is giving you problems... also, use a different outlet(or house), surge protector... could be "brown-outs"...

 

[wuk]

I have seen busted USB ports cause shutdown issues... you only have Keyboard, mouse, and monitor connected right? in the back? Check to make sure you had the front connections connected the right way... having them reversed could cause issues. Maybe you had a 2 part issue.... bad case and bad mobo... or bad mobo and bad PSU....

Weird issue, and I have no other ideas for you sorry.. just thought I would throuw this out there. Plug in the headers one at a time and run tests, should be bale to isolate what connection is giving you problems... also, use a different outlet(or house), surge protector... could be "brown-outs"...

yeh just keyboard and monitor, not even mousee

thanks for the advice. the system has stayed powered on now while mounted inside this case for a good while now so i'm going to start connecting things and see what makes it die.

i'll start with the USB!

cheers

peace and love
will

 

[CaedenV]

for a ground test go to your local hardware store and look for something like this:
http://www.homedepot.com/h_d1/N-5yc1v/R-202867890/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053
To test ground in the case you would need a multimeter, and know how to use it.

To turn the computer off without the header just bridge the jumper.

Dumb question... have you reset Bios or tried updating Bios to see if that fixes anything?

The USB thing could be it as well, worth looking into.

Keep us posted! Good luck!

 

[wuk]

for a ground test go to your local hardware store and look for something like this:
http://www.homedepot.com/h_d1/N-5yc1v/R-202867890/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053
To test ground in the case you would need a multimeter, and know how to use it.

To turn the computer off without the header just bridge the jumper.

Dumb question... have you reset Bios or tried updating Bios to see if that fixes anything?

The USB thing could be it as well, worth looking into.

Keep us posted! Good luck!

thanks! seems to be running OK now so far with the HDD, ODD and USB frontpanel connected so so far i havent isolated the cause yet - im pretty sure it cant be the outlet because the system will run for hours and hours with the MB outside of the case with no problems, (whether PSU is inside case or otherwise)

i have not updated bios on this new motherboard yet. but i did try that on the old motherboard but it didnt add any feature of note and only addressed something to do with the hard disk and someting to do with newer CPUs i think. and of course the crashes still kept happening..

i think this has been on long enoough now with the USB connector so its time to move on to the switches and LED connectors... after this short prayer to the PC god!

love and peace
will

 

[wuk]

thanks to you both for your help!

i have since found that the system shut itself down after about 10 minutes with the USB and led/switches connected.

so i disconnected the led/switches and ran with just the USB intending on leaving that running overnight to confirm but this time it failed within a minute!

the only time i have managed to make the system stay on for a long period of time so far is when the motherboard was outside of the case completely and withoout any connectors except HDD and a usb ODD and i left it with max CPU usage for 3 hoours and it did not shut down!

i should add that while troubleshooting the system i have usually been stressing the system every time that i turn it on - with prime95.

anyway im now just running it overnight with the MB inside the case but neither the USB or any other frontpanel connectors attached and will hopefully find that it is still running in the morning! its nearly 5am here and i need sleep..

thankyou both once again

love and peace
will

 

[wuk]

hey ppl !!

this system shut down overnight while the mb was inside the box but without any frontpanel connectors attached. im thinking i could try running it off of a usb ODD without any ither connectors attached (like not using sata hdd or odd) and seeing if it still shuts down but basically im completely lost here because so far the only consistency is that the system does not shut down when it is completely detached from a physical case (ie no connectors at all) while sitting on the bench.

any ideas at this stage will be greatly appreciated.

thanks in advance

love and peace
will

 

[jdenova007]

Wow... ok... lost myself...

Are you certain it's not an over-heating issue... the case has proper airflow I take it? What if you have it in the case with both of the side covers taken off..? what if you run the motherboard IN the case and the Power supply OUTSIDE of the case..?

I am just throwing random crap out there now, because it's a weird issue. Can you run a stress test from a bootable CD without the HDD connected?

 

[wuk]

Wow... ok... lost myself...

Are you certain it's not an over-heating issue... the case has proper airflow I take it? What if you have it in the case with both of the side covers taken off..? what if you run the motherboard IN the case and the Power supply OUTSIDE of the case..?

I am just throwing random crap out there now, because it's a weird issue. Can you run a stress test from a bootable CD without the HDD connected?

hey thanks for the ideas but unfortunately yes i have checked its not because of overheating and i have already tried all of the above suggestions. it is weird as hell. both motherboards seem to only work when outside of the cases - no matter what other things are connected - even if only with a cd drive connected (usb or sata)

it also shuts down if outside the case with any front panel connectors.

if mb outside the case but only connected to hdd and/or dvdrw (which are inside case) seems to be ok.

whether psu is inside or outside case doesnt seem to matter.

the fun continues.. day 5 with this beast begins after i sleep. lol

thanks mate

love and peace
will

 

[jdenova007]

can you try a completely different case? like a totally different model?

 

[wuk]

can you try a completely different case? like a totally different model?

yep i did and when that failed thats when i turned to tomshardware for help cos ive always found answers here when googling probs in the past.

cheers

i think i need to attempt a completely different approach somehow but im out of ideas.

i might try a 3rd psu tomorrow if i can borrow one from somewhere but meh.