Showing posts with label computer repair. Show all posts
Showing posts with label computer repair. Show all posts

Sunday, December 26, 2010

How to Troubleshoot a Dead Motherboard/Computer

How to Troubleshoot a Dead Motherboard/Computer


Q. How do you troubleshoot a dead motherboard? (Orignally... I purchased an EP-MVP3G. I'M having a problem powering- up the motherboard... Do you have any suggestion?)

A. Try these steps:
• Disconnect the power cord form the power supply, be sure the power supply is set for 110 or 220 volts depending on your location and power and double check it (most have a 110/220 switch)

• Feel/look at the back of the power supply to determine if the fan is working.

• If not, trouble-shoot the power supply and replace it if necessary.


• If the fan is working, try another power supply anyway.

• Plug the computer directly into a known-good (a lamp works) power outlet

• Check to be sure you do not have a motherboard stand-off in the wrong position and shorting-out the bottom of the motherboard.

• Inspect/shake and listen for loose metallic objects (loose screws) on top of and under the motherboard and in expansion board slots

• Look carefully at the ISA and PCI slots, see if any of the contacts got bent/shorted-out. Sometimes an expansion board will dislodge one and it will be pushed into the bottom of the slot.

• Inspect the motherboard for broken or burnt components.

• Carefully inspect the motherboard for black soot from bad bearings and clean and replace the culprit.

• Look for bent/shorted pins on the motherboard headers and straighten.

• Be sure the speaker is plugged into the motherboard. If you hear beeps. Decode the beep code.

• If not, double-check all jumpers.

• Push down on all chips that have sockets in attempt to reseat them.

• What CPU are you using? Be sure the core voltage is correct.

• Be sure the CMOS battery jumper is in the correct position. Some distributors purposely ship motherboards with the jumper in the wrong position.

• Find the jumper that clears the CMOS, put it into the clear position for several minutes, put it back in the normal position, plug-in the power cord, and push the power-on button. If you apply power to the motherboard with the jumper in the clear position you may damage the motherboard.

• Pull all boards except video.

• Disconnect all cables going to all drives, pull all cables except power, power on, and speaker, connect the power supply to the motherboard (the black wires go in the middle on AT power supply connectors--"Black OK, red your dead"), reseat the memory, plug-in and screw-down the display adapter and nothing else (push down on the top, front of the adapter and make sure it is properly seated by looking at it all along the PCI or AGP connector), connect the power-on switch and the speaker.

• Check the monitor plug for bent or pushed-in pins, connect the monitor and nothing else. Check the monitor power cable.

• Reseat/replace the memory.

• Check for Motherboard Electrolytic Capacitor Failures

• Check the CPU for bent pins.

• Try another processor. Note: If you apply power to a motherboard with an Athlon or Duron processor without the CPU fan connected, even for a few seconds, you will fry it.

• Check the CMOS battery with a multi-meter. Should be around 3 volts (2.8 is ok).

• Try a different video board.

• See if the CPU and memory will work with another motherboard.

• Pull the motherboard, set it on the box it came in, install video, memory, CPU, power, and power on. See if it boots. I have seen several instances where this works when the board will not work in the case. And, when reinstalled in the case, it continues to work. I have also seen where it didn't work out of the case immediately, but did work the next day and continued to work. One of those mysteries.

• Replace the motherboard.

Computer Repair & Troubleshooting Tips

Troubleshooting & Repairing PCs

The application of deductive techniques in solving computer system problems is called “troubleshooting”. Effective and efficient troubleshooting involves gathering of clues, investigation, and applying deductive reasoning needed to isolate a problem. Once the cause of a problem is known, you can follow a process of analyzing, testing, and substituting good components for each suspected bad component to find the specific part that has failed. Good deductive reasoning is used to isolate a failure to a particular group of components or chips. Then, circuit analysis is used to reduce the problem to a specific component.


The primary objective of troubleshooting is to restore to normal operation malfunctioning computer systems within reasonable time, cost, and effort.


Basic Requirements in Troubleshooting Computers:
1. Adequate background in electronics
2. Adequate background in computer systems hardware architecture and organization
3. Knowledge in computer systems hardware components and interconnection
4. Knowledge in computer systems operation
5. Knowledge in the use of test instruments and equipment
6. Knowledge in computer programming is an advantage, but not required

Skill Levels in Troubleshooting Computers
1. Peripheral level skill (the ability to locate a defective peripheral)
2. Card level skill (the ability to locate a defective card or circuit board)
3. Component level skill (The ability to locate a defective component or IC)

General Steps in Computer Troubleshooting & Repair
1. Don’t Panic
2. Observe Conditions (including visual inspection)
3. Use Your Senses
4. Clean & reset the connections & system unit
5. Retry
6. Assume a Problem
7. Use correct technical reference data
8. Symptom Analysis
9. Diagnose to a section (fault identification)
10. Localize to a stage (fault localization)
11. Isolate to a failed part (fault isolation)
12. Use correct equipment and software to aid in repair
13. Repair
14. Test and verify


CAUTION: Modifying and removing components from the circuit boards in your system may void the manufacturer’s warranties.

CAUTION: Discharge static electricity present in your body before troubleshooting or repairing any part of your computer system.

CAUTION: Uninformed repairs can cause more damage.