Sign in with
Sign up | Sign in
Your question

Does not turn on, cmos loss

Last response: in Components
Share
May 27, 2011 9:14:46 AM

Hi, i have mounted a new pc, reusing my old PSU, HD and DVDR and some curious occurs: If the pc was disconnected from mains, does not turn on, no turning fans, etc, only a led in the MB built in power switch. Then if i disconnect from mains, wait until the led turns off, and reconnect to mains, the pc turns on correctly, but the cmos was deleted and i must enter bios setup and save to cmos. After this everything is OK... until i switch off the pc

What could be wrong? PSU? MB?

Thanks.

More about : turn cmos loss

May 27, 2011 10:00:13 AM

When i told "some curious occurs: If the pc was disconnected from mains, does not turn on" i obviously want to tell is "some curious occurs: If the pc was PREVIOUSLY disconnected from mains, does not turn on"

Another tough is the PSU was running fine on my previous pc, but, may be incompatible? Is connected to MB by 24 pin ATX connector but only 4 pin 12 volt connector on the MB's 8 pin.
a c 144 ) Power supply
May 27, 2011 11:34:10 AM

Looks like two problems.

Sounds like you need a new CMOS battery. That should fix your "CMOS deleted" problem.

System not booting sounds like a problem in the PSU circuits and turn on the power supply.

System specs?
Related resources
May 27, 2011 2:11:00 PM

I recently found that if the psu is always connected to mains, does not power on too, really does not matter if was connected o disconnected. The thing is if the pc was switched off some minutes the pc does not power on. The cmos battery is the first thing i have checked: 3.2 v., correct.

I have made another test, i have tested with another PSU, and the symptoms are the same, so i am thinking the problem is the MB. Simply if the cmos is corrupted or deleted it refuses to power on until recycled disconnecting and connecting from mains. Could be that correct?

The MB is brand new, an ASUS P8Z68 V-PRO, with a SB 2600K and a sapphire 6870.
a c 144 ) Power supply
May 29, 2011 2:08:41 AM

What PSU's?
May 29, 2011 5:20:53 AM

jsc said:
What PSU's?


thermaltake purepower 460 and other unbranded
May 29, 2011 6:41:05 AM

Hi, have you checked for a new bios upgrade? and is the clear cmos jumper in the right place?
May 31, 2011 6:33:58 PM

blakmumba said:
Hi, have you checked for a new bios upgrade? and is the clear cmos jumper in the right place?


Jackpot! The jumper was not in wrong place... nor right place, was not any jumper, factory missing. Placed in place and problem solved.

Thanks very much!
June 27, 2011 12:29:40 PM

isomax said:
Hi, i have mounted a new pc, reusing my old PSU, HD and DVDR and some curious occurs: If the pc was disconnected from mains, does not turn on, no turning fans, etc, only a led in the MB built in power switch. Then if i disconnect from mains, wait until the led turns off, and reconnect to mains, the pc turns on correctly, but the cmos was deleted and i must enter bios setup and save to cmos. After this everything is OK... until i switch off the pc

What could be wrong? PSU? MB?

Thanks.



I bought my New PC and using everything new except my old monitor and i'm also facing the same problem

my configuration is as follow

intel i5 2500k
ASUS P8Z68-V
COOLER MASTER 600W PSU
CORSAIR 4 GB 1600mhz
SEAGATE 1 TB HDD


Now my problem is that when ever thing is off and i start my PC by

1. power on the plug in wall and then push power button of my CPU cabinet, NOTHING HAPPENS, i mean computer doesn't boot but at the same time a power button on motherboard is on and showing stable red light so that i can push that button and start the computer but even though that onboard power button is showing light, when i press that power button on motherboard COMPUTER DOESN'T BOOT EVEN NOW.

but when i again swithoff the power from wall socket ( i don not pull out the plug from wall socket now ) and again power on from wall socket and press the power button of cabinet , THIS TIME COMPUTER BOOT AND TAKE ME TO THE AMERICAN MEGATREND SCREEN SHOWING " PRESS F1 TO RUN SETUP".


can any one tell me what is this, and how can i resolve this issue.

I have already updated my bios from asus website, i am now overclocking now and just using the default settings.

Thanks.
June 27, 2011 12:33:58 PM

isomax said:
Jackpot! The jumper was not in wrong place... nor right place, was not any jumper, factory missing. Placed in place and problem solved.

Thanks very much!




How to solve that i'm also facing the same problem please tell me which/where is that jumper that i need to place before my pc also start working fine that it is working fine for this person.


Please help me i'm in big problem
June 27, 2011 12:37:43 PM

blakmumba said:
Hi, have you checked for a new bios upgrade? and is the clear cmos jumper in the right place?




Please help me too where is the cmos jumper in motherboard and how to set it to right way.

i'm new to this. please help

i'm also facing the same problem like the other guy "ISOMAX" you helped in this post.

my problem is also same:- my PC too doesn't start after power off from the wall socket and after many try i start working randomly. please tell me the process to set the cmos jumper.


Thanks. i bleave only you can solve my problem. Thanks.
June 27, 2011 5:24:34 PM

Hi, really the problem seems to be the same.

Go to

Download the manual, version E6598

Go to page number 2-20, chapter 2, paragraph 2.2.7. Here explains where the jumper is, and which is the correct position (normal (default)). You can get (if missing) the jumper from an old motherboard or from an old other computer equipment (hard disk, floppy...)

If the jumper is missing, please say it, could be a good idea to asus take note of this and correct this random circumstance in the production chain at factory... i should say it in a thread i opened in the asus forum.
June 28, 2011 12:28:36 AM

isomax said:
Hi, really the problem seems to be the same.

Go to

Download the manual, version E6598

Go to page number 2-20, chapter 2, paragraph 2.2.7. Here explains where the jumper is, and which is the correct position (normal (default)). You can get (if missing) the jumper from an old motherboard or from an old other computer equipment (hard disk, floppy...)

If the jumper is missing, please say it, could be a good idea to asus take note of this and correct this random circumstance in the production chain at factory... i should say it in a thread i opened in the asus forum.



You absolutely right, my motherboard was also missing cmos jumper, so i pull cmos jumper from my old motherboard and put it into ASUS P8Z68-V and now it IS WORKING FINE AND RUNNING FLAWLESS.

you solved my problem.

Thanks. Bro.
!