Before performing any of the steps described below, please review and observe the personal safety and electrostatic discharge (ESD) precautions in the following document:
To troubleshoot system board issues, other system components must first be eliminated as possible causes for the problems experienced. Many problems thought to be caused by the system board are actually caused by another faulty component. Quality assurance testing has revealed many of the system boards returned for warranty replacement are not defective.
Slow performance and intermittent shutdown problems are frequently the result of viruses and other "malware". The system should be scanned for viruses and spyware. If possible, the system should be tested with a substitute hard disk drive loaded with a new operating system installation. This will quickly isolate performance issues to the hard disk drive and the operating system on it or to the other system hardware.
If the computer has just been serviced, suspect the replacement parts are incorrect or incorrectly installed first. Some older system boards use voltage regulators or regulator jumper blocks. Make sure these are correctly installed. Make sure the part numbers used are correct before continuing. Suspect defective replacement parts only after verifying part numbers.
- If either the system board, processor, or system security chip have been replaced, reflash the BIOS to the latest level before proceeding.
- Do not use Netfinity BIOS diskettes included with some replacement desktop system boards as they will render desktop machines inoperable. Only use the BIOS code prescribed for the computer being serviced.
Refer to Troubleshooting power issues - System will not power on to eliminate common no power problems as causes of a no power condition.
Refer to Troubleshooting startup or booting issues or any of the other symptom related topics in the Troubleshooting index before suspecting the system board is defective.
- Continuing beyond this point assumes there are no external power failures affecting system operation.
- Continuing beyond this point assumes components other than the system board, processor, and power supply have been checked and are known to be working properly.
- Determine if anything has changed since the system last worked correctly. This includes new hardware or software. If possible, these changes should be reversed.
- If the system was moved, even if only slightly, just before the failure, reseat all components. Loose parts are frequently the cause of erratic operation.
The following steps are complex and a high level knowledge of computer hardware is required to perform them. They involve multiple component removals and should not be attempted by persons not familiar with these procedures.
- Look for physical signs the system board has failed. This may require removal of one or more components.
- Look for burn marks or other evidence of electrical shorting on the system board.
- Look for swollen or leaking capacitors.
- Look for broken sockets and connectors.
- Look for burned wiring including the ribbon cables.
Replace any burned or broken components.
- Test the power supply.
- Refer to the Hardware Maintenance Manual directions for testing the power supply.
- Some newer power supplies are equipped with LEDs to indicate power supply and system board diagnostic conditions. Refer to the table below, observing the state of the power LED on the front of the computer and the 2 diagnostic LEDs on the power supply to determine the condition:
||This is the normal condition of the LEDs when the power is OK.
||Make sure the power cord is attached to a working electrical outlet.
If the electrical outlet is OK, replace the power supply.
(after the power button has been pressed)
||Replace the system board
||Replace the power supply
If the power supply test fails, replace it.
If the power supply passes, proceed to step 5.
- Perform a dead system test.
- To eliminate other system components as defective and eliminate possible chassis shorts, remove the system board from the chassis and place it on a non-conductive surface to protect against ESD damage.
- Reconnect the minimum components required for testing. These include all connections from the power supply to the system board, the processor and heat sink. A connection from the power switch may be needed.
- The memory should be removed.
- All video, network, or other option adapters should be removed.
- All drives and cables should be disconnected.
- All monitor, mouse, keyboard, printer, and other connections should be removed.
- Make sure all jumpers are in their correct position. Refer to the systems Hardware Maintenance Manual for correct jumper settings.
- Look for bent or broken pins in controller sockets and other attachment locations.
- Check the battery. Weak batteries typically are the cause of date and time errors at system startup.
The system under test should now consist of the system board with power supply connections, and the processor with heat sink attached.
Note: Some devices can become "bit locked" and result in a dead system. These devices may begin working correctly after being removed and reinstalled.
- Power on the computer. Care must be taken to avoid system board to electrical ground shorts when the system board has been removed from the chassis.
- If no beeps are heard and no power supply activity is evident, either the system board or the processor is defective. There is no test to determine which is defective other than by swapping parts. If possible, move the suspect processor to another working system. If that system continues to work, the suspect system board is probably defective.
- If a series of beeps are heard, the processor is working to some extent, and probably was not the cause of the no power symptom. Some system boards do not have a beeper and will remain quiet. In this case, there should be some indication of power at the power supply, such as the power supply fan turning. The system has moved from a condition of having no power to showing some signs of having power. The cause of the dead machine symptom has been removed.
Continuing beyond this point assumes the components added in these steps have been tested and verified as working properly. These tests should determine if a section of the system board is defective. Using components not known to be good may result in incorrect conclusions. If the installation fails, retest the added part again before replacing the system board.
- Begin adding components to establish the quality of the individual system board component sections.
- Power off the system.
- Add the minimum number of memory chips required for system operation. If in doubt, add one.
- Connect a monitor to the onboard video connection. Add a video adapter if no onboard connection exists.
- Power on the monitor and computer. A series of beeps should be heard. Video should be present. If no video is present, power off the system and add a second memory chip if it was previously installed. If no video is present and the installed memory is known to be good, perform a boot block recovery procedure. Refer to the Hardware Maintenance Manual for additional information.
- It the system still fails to display video, one of the newly installed memory chips or monitor is defective or the previous troubleshooting was incorrect.
- Power off the system.
- Connect the diskette drive to the system board. If no diskette drive is available, add a CD-ROM drive. Make sure the CD-ROM is configured as the master device on the primary IDE controller. The purpose is to add a device to boot from, but preferrably not the hard disk drive.
- Add a keyboard. Do not add the mouse.
- Power on the system. A series of beeps should be heard. Once the system completes the power on self test (POST), enter the System Configuration Utility and verify the settings for the current configuration are correct. Make sure the Startup Sequence shows only the diskette drive or CD-ROM drive added in step 7, and shows it as the first boot device. Save the settings and exit. Power off the computer.
- Flash the BIOS using either a diskette or CD-ROM. This step should prove the diskette or CD-ROM controller is operable and the system can boot to the installed drive. Remove the disk from the drive when complete.
- Boot to a bootable diskette such as the IBM Enhanced Diagnostics. An image is available for some systems so the DOS based diagnostics can be burned to a writable CD if necessary.
- Run the IBM Enhanced Diagnostics.
- Investigate any errors reported.
- Power off the computer. Add the hard disk drive.
- Do not remove the IBM Enhanced Diagnostics from the drive.
- Configure the hard disk drive jumpers to be the master device on the primary controller. If installed, configure the CD-ROM drive to be the master device on the secondary controller.
- Power on the computer. A series of beeps should be heard. Once the system completes the power on self test (POST), enter the System Configuration Utility and verify the settings now show the hard disk drive. Make sure the Startup Sequence shows the hard disk drive is not configured to be the First startup device. The diskette drive or CD-ROM drive should remain as the First startup device. Save the settings and exit. The system should begin to restart.
- If properly configured, the computer should boot to the IBM Enhanced Diagnostics. Run the IBM Enhanced Diagnostics again.
- Although the hard disk drive should have already been checked as working properly, this will test the controller section of the system board and test the hard disk drive for unknown problems. It will also test the secondary controller if the CD-ROM was installed.
- Investigate any errors reported.
At this point, if no errors are reported by IBM Enhanced Diagnostics, it is unlikely there is any fault with the system board. Major sections of the system have been tested as working.
- Reassemble the computer. Add the more likely to fail or more suspect connections first. Test system operation after each component is added to make sure the system continues to work correctly. Return individual components one at a time and continue with system board section testing.
- Refer to "Need more help?"
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