Laptop POST Troubleshooting Guide
From Desktop Build, you should be familiar with POST troubleshooting. In Laptop Build, working with a built-in LCD monitor and other integrated components can make things a little trickier. Start working through this guide to narrow down the nature of the problem, and best case scenario, get the machine up and running.
Identify the cause
Work through these questions step-by-step, using the guides below.
- Is the system getting enough power?
- Is the system failing power-on self-test (POST)?
- Is the LCD panel dead?
- Is the graphics card or motherboard failing?
1. Is the system getting enough power?
- You can't get into BIOS
- The screen remains dark
- None of the indicator lights turn on (no signs of life)
- Troubleshooting steps
☐ Remove the battery.
☐ Troubleshoot your AC adapter.
- Try using a different AC adapter with the same power rating.
- If possible, try using an AC adapter that has a higher amperage (A) than required.
- If you're not sure if an AC adapter is functioning, use a multimeter to test. Full instructions are in the appendix article on AC adapters.
☐ If you still aren't seeing any indicator lights after this step, then this system is dead. Consult your instructor to see if it should be recycled, or saved for parts.
☐ If the indicator lights come on, but it's still not showing anything on the screen, proceed to the next section.
2. Is the system failing POST?
POST is run automatically before the process of loading the operating system is begun. POST is intended to prevent software errors caused by malfunctioning hardware.
Is the system completing POST without video output?
☐ Check the optical drive
- Turn the system on, and put your hand over the optical drive. If it spins up, the system is completing POST. This means you have a video problem to troubleshoot, use section 3.
☐ Take a close look at the LCD screen
- Power the system on and look for a very faint outline of text or images on the screen. This is caused by a dead LCD backlight. Consult with your instructor about a possible screen swap.
☐ Check for flashing indicator lights
- If you notice flashing indicator lights, or if the drives are not spinning up, the system is failing POST. Continue reading through this section.
What causes POST failures?
There can be many reasons a system may show some indicator lights, but won't boot. Here are some common reasons that we can troubleshoot for:
- A bad or incompatible PCI or PCMCIA card (usually a wireless card)
- Bad or incompatible RAM
- An integrated component on the motherboard (GPU, Host Bridge, etc) has failed
☐ Remove wireless cards
- Remove any PCMCIA or internal wireless cards, and try powering the system on.
- If the system still doesn't POST or boot to BIOS, follow the RAM test instructions.
☐ Troubleshoot RAM failure
- Remove the RAM' currently in the system and set it aside. Take note of the speed and type (i.e. DDR2-667).
- Grab 4-6 sticks of RAM of the same type and speed from the sorted bins. Keep in mind these sticks are untested, and may not work.
- Starting with the first DIMM slot, try powering on with one stick of RAM at a time. If you find a stick that works, try the other slot. If you are unable to power on with RAM in the first slot, try several sticks in the second slot.
- If the machine does not POST after trying several different sticks in both RAM slots, the machine is likely dead. Ask your instructor what to do next.
3. Is the LCD Panel Dead?
- The system will not boot to BIOS
- The screen doesn't display the correct video output, or any at all
- The system appears to complete POST
- Failed LCD assembly component (inverter, backlight, panel, etc).
- Video output problems unrelated to the LCD panel
☐ Test with an external monitor
- While the laptop is powered off, connect it to an external monitor via the VGA port. Make sure the external monitor is turned on, and is set to display analog input.
- Newer laptops may have a different kind of video output. Check with your instructor if you have questions.
- Power on the laptop.
- Some models will automatically detect the external display, and immediately begin displaying on the monitor. Others require you to hit a SoftKey combination to send the video output to the external monitor (e.g., Fn + F7).
- Not all laptops are able use an external monitor during POST. If this is the case, consult your instructor to see whether the system should be recycled or made into a parts machine.
4.Is the graphics card or motherboard failing?
If the the steps listed above haven't shown any results, then most likely the issue preventing the system from working properly is related to the motherboard and/or its video chipset. Unfortunately, methods to repair these sorts of issues are beyond what we can do at Free Geek. If a machine is not able to POST after following the instructions above, it needs to be recycled or saved for parts. Ask your instructor for further instructions.