sanshairo Posted February 19, 2012 Share Posted February 19, 2012 I had a strage problem lately.. My PC started to automatically restart suddenly. So I thought it is overheating, and cleaned it from dust inside. Then, it refused to power on. It does power on for 1/2 sec, then switches off. I tried several options, like removing GPU, removing HDs, CMOS battery, ... etc. It did not work. But.. It turned on successfully after removing the PSU wires connected to CPU on the motherboard. The PC now is ON, but obviously there is no CPU. When I put these wires back in, the original problem comes back, turning off after 1/2 sec only. I am not sure where the problem is. Is it PSU? Is it CPU? Is it motherboard? Please help.. Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/ Share on other sites More sharing options...
Detection Posted February 19, 2012 Share Posted February 19, 2012 Could be the board, CPU or PSU Your gonna have to try a new PSU to rule that out, and then the rest one by one until you find the cause, PSU is easiest first though Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594666534 Share on other sites More sharing options...
MFH Posted February 19, 2012 Share Posted February 19, 2012 I'd place my bet on the PSU? Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594666562 Share on other sites More sharing options...
sanshairo Posted February 19, 2012 Author Share Posted February 19, 2012 You think so? I ordered a new PSU, 700 W. Hopefully the problem gets solved, coz buying a new MB or CPU would be much more costy.. Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594666632 Share on other sites More sharing options...
mjedi7 Posted February 19, 2012 Share Posted February 19, 2012 Sound like a faulty PSU! try using another PSU or a PSU tester ! Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594666650 Share on other sites More sharing options...
rkenshin Posted February 19, 2012 Share Posted February 19, 2012 Sounds like a faulty PSU. It probably isn't able to provide stable power on the voltage rails to power all the components successfully. Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594666666 Share on other sites More sharing options...
Eric Veteran Posted February 19, 2012 Veteran Share Posted February 19, 2012 Check the capacitors on the motherboard. The tops of them should be completely flat. If any are bulging (or worse, have gunk leaking out of them) then it's the board and you'll either have to replace it or the capacitors. Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594666682 Share on other sites More sharing options...
n_K Posted February 19, 2012 Share Posted February 19, 2012 (edited) Doesn't sound like PSU to me... It'd either be undervolting the CPU in which case it wouldn't do anything, or overvolting it in which case the CPU would blow or a cutout would happen, but afaik the cutout would be present if the CPU was in or not as it's checked by the motherboard. Capacitors could be causing the problems but if it's a relatively new M/B (less than 3 years old) there should be no cap problem what-so-ever unless you get a very VERY cheap budget board. Did the CPU feel warm on it's heatsink? Is there any thermal paste on the CPU or the M/B CPU pins? edit; Wait I read it wrong, you mean the 12V wires to the CPU, but the CPU is still in the socket? Try removing the CPU and powering on with the 12V wires in (if you've got a multimeter, you could also check the voltage it's putting out) and see if it turns off still. Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594666694 Share on other sites More sharing options...
lars77 Posted February 19, 2012 Share Posted February 19, 2012 This might be a longshot, but while you were cleaning it did you happen to budge the CPU's heatsink/fan? You might want to double-check that it is still exactly on top of the CPU with no space in between the CPU & heatsink. Or even reseat the heatsink on top of the CPU. I only say this b/c it happened to me once, & the computer would basically shutdown within a second or two b/c the CPU would keep overheating without the heatsink on properly. Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594667012 Share on other sites More sharing options...
sanshairo Posted February 20, 2012 Author Share Posted February 20, 2012 So here is what I did.. I removed the heatsink/fan of CPU, and cleaned it. I removed the CPU, cleaned the socket, and applied new thermal paste and connected the heatsink one more time. All using air cans. It did not work. I bought a new PSU, same problem. So it is definitely not a PSU problem. I removed the CPU from socket, and kept its power cables connected to MB. Same problem occurred, except that now after turning off it goes on then off then on then off again, in a loop. All capacitors on the motherboard seem to be fine. my MB is MSI x58 platinum. Shall I buy a new CPU? or a new motherboard? :( Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594668210 Share on other sites More sharing options...
HyBry Posted February 20, 2012 Share Posted February 20, 2012 Did you have the CPU overclocked? You might have fried the CPU power socket on the board so when it is plugged in it shorts the PSU so it wont turn on. Also you are sure you mobo is not shorting anything after the cleaning, like touching the case? My guess would be that it is mobo, which hopefully has not left lasting effect on CPU. Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594668644 Share on other sites More sharing options...
neoraptor Posted February 20, 2012 Share Posted February 20, 2012 get the mobo out of the case (put it on some books or something), reseat ram video and cpu (be sure there is enough thermal paste and the heatsink is placed properly) and remove everything else. Remove the battery for couple of mins, then put it back and connect the psu. Also leave minimum ammount of ram. Connect the speaker and listen for beeps. If still nothing happens disconnect video and again listen for beeps, same with ram. If still nothing cpu or mobo is probably bad Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594668680 Share on other sites More sharing options...
helpifIcan Posted February 20, 2012 Share Posted February 20, 2012 ^^^^^^ What the above poster said! ^^^^^^ Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594668720 Share on other sites More sharing options...
HawkMan Posted February 20, 2012 Share Posted February 20, 2012 get the mobo out of the case (put it on some books or something), reseat ram video and cpu (be sure there is enough thermal paste and the heatsink is placed properly) and remove everything else. Remove the battery for couple of mins, then put it back and connect the psu. Also leave minimum ammount of ram. Connect the speaker and listen for beeps. If still nothing happens disconnect video and again listen for beeps, same with ram. If still nothing cpu or mobo is probably bad Don't put naked electronics on paper,paper is highly ESD conductive. Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594668738 Share on other sites More sharing options...
neoraptor Posted February 20, 2012 Share Posted February 20, 2012 Thanks HawkMan for the correction - antistatic bags then. I had never had problem with paper/magazines/etc but agree Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594668756 Share on other sites More sharing options...
sanshairo Posted February 21, 2012 Author Share Posted February 21, 2012 Okay.. So I tried a new CPU and the problem is the same.. It is a MB problem, it seems.. I will get a replacement tomorrow. I will buy it from the used market, so which do you recommend? 1) MSI X58 Platinum (2008 model) --> this has the advantage that I just plug and play, no need to re-install anything because my MB was the same model. 2) MSI X58-GD65/GD45 (2011 models) ? Not sure if I get a performance boost that is worth the trouble of installing my OS and other things.. 3) Other brands? What do you recommend? I have 1366 socket, core i7 920 CPU, 9 GB RAM. Link to comment https://www.neowin.net/forum/topic/1058928-urgent-pc-turns-on-only-after-removing-power-to-cpu/#findComment-594670366 Share on other sites More sharing options...
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