View Full Version : Laptop Repair Intro

03-17-2008, 08:50 PM
Ok, first off, I wrote this a while ago and thought it'd be worthwhile to share. Several months ago we took on an intern as part of some high school, work/learn program deal. The idea was to make a guide for general guide for him, focusing on computer repair, mostly laptops (since most techs don't have experience with them). Forgive me, it's written a little more formally than I usually write because he wanted to use it in his class....

I'm thinking about adapting this into some sort of check list/guide for new hires (not that I'm anywhere close to hiring someone at this point). Any input, or general comments?

As computer technicians, part of our job is keeping up with new hardware and software so that we can better serve our customers. Though laptops are hardly new technology, they are being more widely used and are expected by many to outsell desktops in 2008. It’s important for repair techs to start to become familiar with laptop repair and basic troubleshooting.

This guide is intended to give an insight into some of the most common problems specific to laptops and how to correctly diagnose which components are at fault. This is not an extensive guide on all problems and is only meant to help with the basics of laptop repair.

I divide most laptops up into four different sections for repair and disassembly:
1. Keyboard/covers/drives – the parts that are generally easily accessible to an end user
2. Screen assembly – The hinges, lcd, inverter and plastic housing
3. Top and bottom cover – the plastic case
4. The motherboard – The motherboard, cpu, heatsink/fan and and daughter boards

Most systems are easily disassembled following this order. Keeping the screws divided into these groups also helps to make sure none are left over or installed into the wrong places.

Problem: No power, battery is not charging.

Solution: When a desktop has no power, the first thing a tech will usually check is the power supply. The same procedure applies to laptops. The very first, and easiest, part to check is the power adapter. Using a voltmeter, check the leads on the power adapter tip to ensure that the right voltage is being produced. The correct voltage should be listed on the adapter’s label. Some adapters will also produce a high pitched squeeling noise which is almost always an indication that they’ve failed. If available, try another adapter, even if the adapter tests ok.
Broken or loose power jacks are a very common problem related to no power symptoms. Repairing the power jack requires disassembly to the motherboard level and the ability to desolder the old and solder the new jacks. Some systems have a separate board that can be replaced and in some cases this is a better option than resoldering a new jack.
The final common power problem involves the motherboard or the battery itself. Some batteries fail and can cause the system to not power on normally or accept a charge. Additionally, the motherboard itself may have a failed voltage regulator or capacitor, but that type of diagnosis/repair is outside of the scope of this guide.

Problem: Dim screen, screen goes dark after time.

Solution: There are two common components that fail when a screen is dim, the lcd power inverter and the lcd backlight itself.
The lcd inverter is responsible for brightness and converting the dc current back to ac for the ccfl (cold cathode fluorescent light). The inverter is typically located behind the front plastic bezel on the lcd. To access it, peel back the rubber stoppers from the bezel and remove the screws. The plastic bezel should snap off to reveal the screen and inverter. There are two quick methods to test an inverter: Plug in another screen’s backlight (usually the pink and white wires) into the inverter and turn the system on. Or, using a voltmeter, place both leads very close together and wave them near the inverter (without actually touching the inverter). (If the inverter is working, this method will show a fluctuating voltage on your meter. You can actually do this without taking off the plastic bezel, but I don’t consider it as a reliable a test.)
As I mentioned before, the backlight itself may also be bad. One symptom of a bad backlight is a flash of red after the system is turned on, right before the screen goes dim. Additionally, if the system was dropped, the backlight may have broken. The best option in the case of a bad backlight is to replace the lcd itself. Replacement screens can almost always be found using the model of the screen itself as opposed to the model of the system, and for a much better price.

Problem: Overheating

Solution: Because of the relatively smaller heatsinks, vents, laptops are especially prone to overheating. As with a normal desktop, cleaning the heatsink of dust will usually solve most heat issues. Some systems have a panel to easily access the heatsink and cpu fan, while others need to be disassembled to the motherboard level to be adequately cleaned. If removing the heatsink is necessary, always replace the heatsink compound, preferably with a high quality paste.

03-17-2008, 10:53 PM

v good

Bryce W
03-18-2008, 11:48 AM
A+++++++++++. Would buy again. ;)

03-18-2008, 12:09 PM
Don't you be giving him ideas now! ;)

03-18-2008, 09:19 PM
I would just like to add that the first step before I actually go into testing the AC adapter for power failures is to try and start the laptop with only battery and then with only ac adapter without battery. That gives me a quick idea as to were the problem lies, not important but just what I do.

Nathan H
03-19-2008, 12:29 AM
Well done, 10/10

What I would do differntly is: A Laptop with no power, I would firstly try a different Power pack (One that I know works) (I have a replacement pack with has multiple connectors inc a dell connector, and is multi voltage)

This way I immediatly know if its the laptop or not thats faulty.

I in now way imply that your guide is wrong, far from it its great, its just what I would do differently

03-19-2008, 12:36 AM
Yeah, I actually do always try another adapter. I mentioned "try another adapter, even if it tests good", just because even if the voltage is correct, that doesn't mean the adapter works under a load.

I'm thinking up next for this, I want to write some stuff about differences between manufactures. For instance: If you have an acer that locks up in windows, it could be a faulty battery. Removing the battery or disabling acpi monitoring will allow the system to work correctly..... Or how some Dells won't charge the battery without a genuine dell adapter.
I'll update that when I have time, but if anyone knows of any manufacturer's quirks like that, feel free to share!

07-06-2010, 03:31 AM

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