Pc turns on and off

F

fsbee

Geek
Running out of options with a home built rig, designed to be a media centre.
The Problem:
. When I turn it on, the fans (PSU fan as well) start for a second and then turn of for a second, then just keeping going on and off until I turn off at the PSU.
The Computer.
Intel E6300 cpu
Gbyte 965-DS3 m/b
Coolermaster 430W igreen PSU
Corsair DDR2 twinX 1gb ram
250gb Samsung sata2 7200 HD
Alaska AK920 heatpipe cooler
Pioneer DVR111
256 gigabyte 7600PCIe
Pinnicle PCTV dvb-t tuner
XP MCE.2005

The History
Built it without a hitch, booted fine and worked good (was having some pinnacle hi-cups) for about a week. Moved the machine about 6 inches and when I tried to start it the above happened, presumed I shook something lose so checked every connection and card—the same result. Stripped it down completely and re built—same result. Built it out side the case—same result. Removed one component at a time and tried each time—same result. Took right down to motherboard, CPU and PSU,—same result. Did the same with a replacement PSU—same result. Ruled out on/off switch by shorting pins on m/b. I then got on to suppliers who suggested a motherboard fault and I sent motherboard, CPU and PSU back for testing. They have now returned them saying each item tested individually and together and no fault found. Guess what I’ve put them together and of it cycles on/off/on etc. It must be me but just don’t know what to try, have seen similar threads on this and other forums- but never an answer, please help.
Sorry this is so long but have noticed "helpers" seem to often have to ask for more info.
 
I assume you tried resetting the BIOS?

The reason most of these threads don't get answered is because no one has a clue whats wrong!

A Friend who was in a similar situation removed the battery from the motherboard for a few hours, after that it worked (the bios had been reset before) but we have no idea why!
 
Had similar prob with mine about a year ago. Sent M/B, CPU and RAM back for testing. All were fine. After about 30 mins of staring at the motherboard, hoping something would just come to me, it did. There were three pins at the top next to the USB port. Put a jumper on the second two pins and it worked fine. Hope this helps
 
Thanks for your replies, I.d tryed reseting the bios by removing the battery for about 5 mins before I sent it of, didn't make a difference .also in the report from the supplies they said they reset bios as well.
Dont seem to have any spare pins on this motherboard that are not used, but will look again willing to try anything
 
Does your motherboard have something like cool and quiet technology? This I know will control the fan speed fans when the system is at a certian predefined temperature in the bios but im not sure it would turn the fans off.
 
Dont think so. Fans including the PSU one are literally coming on for a second then straight off just as they stop spinning on for a second then off--for ever it would seem.
 
Try starting it barebones:

CPU, Motherboard, PSU and RAM

See if it does the same thing, if it does then you know it's limited to one of those things and seeing as the CPU Motherboard and PSU have been tested it'll probably be the RAM, if it doesn't happen then you know it's a problem with other devices, add them in one by one and see what happens, if the problem starts up again then the device you just added will probably be the problem.
 
Have you tried this in and out of the case, it could be that something's shorting out somewhere and causing this problem.
 
tried in and out, no difference.starting to panic now £800 worth of bits and dont seem to be getting any closer to answer.
 
Yeah I just thought maybe there was something in fsbee's case that wasn't in the case of the people who tested the parts (if they did test in a case)
 
Got it working! did everything everybody suggested-and more,but still kept playing up,then took one of the memory units out and it booted,kept swapping them and changing which slot they are in and found a combination that worked. What do you think the chance of dirty connection are, any suggestions for a safe cleaner that can be used on memory and motherboard?
 
You must log in or register to reply here.
Back
Top