[ The PC Guide | Troubleshooting and Repair Guide | The Troubleshooting Expert | Troubleshooting Specific Components | Troubleshooting the Motherboard and System Devices | CMOS Memory or Real-Time Clock ]

My system has a CMOS clear jumper but when I use it, it doesn't seem to do anything

Explanation: You are following the directions to use the CMOS clear jumper on your motherboard, but the CMOS memory is not being cleared.

Diagnosis: The usual cause of this problem is neglecting to unplug the PC before attempting the procedure, or accidentally changing the wrong jumper. Some motherboards, particularly those using the ATX form factors, are supplying voltage to the motherboard even when it is off, and this is used as a "backup" for the CMOS memory when the battery is not working. (You're not supposed to be working inside the box with the power plugged in anyway, remember?)

Recommendation:

  • Unplug the PC, if it is plugged in.
  • Make sure you are actually using the CMOS clear jumper and not a different one by mistake.
  • Troubleshoot the motherboard.

Home  -  Search  -  Topics  -  Up

The PC Guide (http://www.PCGuide.com)
Site Version: 2.2.0 - Version Date: April 17, 2001
© Copyright 1997-2004 Charles M. Kozierok. All Rights Reserved.

Not responsible for any loss resulting from the use of this site.
Please read the Site Guide before using this material.