My Dell laptop has a power problem

My Dell laptop has a power problem.

The Dell Precision M20 Battery stops charging when I move the power cord on the DC adapter. When I start moving the cord left to right, the power LED light on the front goes on and off and the battery charge LED goes on and off too.

I removed the precision m20 battery and tested the laptop again. The laptop starts fine from the DC adapter when the battery is removed, but as soon as I start moving the power cord the laptop shuts off. It looks like the laptop looses power immediately.

If you have a problem like that, most likely it’s related either to the power adapter or the DC-IN power jack.

First of all, I tested the laptop power ac adapter with a multimeter. The power didn’t cut off no matter how badly I moved the cord. The power adapter output voltage was 15.45VDC all the time. That means there is nothing wrong with the power adapter and most likely there is a problem with with the power socket inside the laptop.

Now I’m going to test the power socket inside the laptop.

In order to access the power socket I had to disassemble the laptop and remove the top cover assembly with the display.

You can find disassembly instructions for many HP, Dell, IBM, Lenovo, Sony and Toshiba laptops in these service manuals and guides.

In the laptop I was fixing (Tecra M2) the power jack is attached to a DC-IN harness and this harness can be unplugged from the motherboard.

As you see, I removed the DC-IN harness from the motherboard, plugged in the power adapter and tested continuity with my multimeter as it shown on the picture.

When the power cord is still, the voltage output is 15.45VDC, the same as on the plug.

But as soon as I start wiggling the plug inside the jack, the power cuts off and voltage goes to 0. It means, the power harness is bad.

The problem was fixed after I replaced the defective DC-IN harness with a new one.

In some laptops the power socket (DC jack) is soldered to the motherboard.
If the battery stops charging when you wiggle the power plug inside the jack, either you have a bad power adapter (test it with a voltmeter) or the power jack is broken or loose.

You cannot simply unplug the jack and replace it with another one. You’ll have to unsolder the old jack and solder a new one back on the motherboard as I described in this post.

If the power jack is not broken but loose (not making good contact with the motherboard) you can resolder the old jack without replacing it with a new one.

If you want to buy a new one,you can see more information from http://www.udtek.com

Dell U4873 Battery Guide

Notebook batteries are common topic of discussion, and the vast majority of questions about them deal with prolonging their lives. There is a lot of information about Lithium Ion (hereafter Li-Ion) batteries to wade through. There are a lot of misconceptions floating around as well. This simple guide addresses the most common notebook battery questions and concerns.

Your notebook battery such as Dell U4873 Battery will deteriorate over time whether you use it or not. Although the Li-Ion industry does not publicize this fact, your battery’s clock began ticking the moment it was assembled. The elements inside your battery slowly react with each other, eventually rendering the battery unable to supply the required power to your notebook. In addition, your battery is rated to last between 300 and 800 charge/recharge cycles. It will gradually lose charge capacity rather than abruptly fail to power your notebook.
How long will the battery last?
The general consensus is that notebook batteries(u4873 battery) last one to three years. While you can slow the battery’s aging and loss of capacity, you cannot stop either decline. The temperature of the battery, combined with the amount and nature of its usage contribute significantly to your battery’s lifespan. You can ease the aging process with some care and maintenance.

Nature of Usage

Li-Ion batteries do not suffer from the memory-effect (requiring complete discharge before recharging to avoid loss of capacity) like older rechargeable batteries. Regular full discharge/recharge cycles result in an increased loss of capacity per cycle. A series of partial discharge cycles are better for Li-Ion batteries than a single full discharge. You should, however, calibrate your battery routinely.

Temperature

Lower temperatures slow down the self-discharge (loss of charge while disconnected) and aging process of the elements within your battery. Therefore it follows that higher temperatures shorten the life of your battery. Leaving your battery connected while on laptop ac power adapter causes the internal temperature of the battery to rise. Removing your battery and storing it in a cool, dry place will help to slow the aging process. Keeping your notebook in a hot environment is also detrimental to your battery.

Amount of Usage

The Lithium-Ion batteries used in notebooks are rated to handle between 300 and 800 charge/discharge cycles. Some of these cycles are used when you leave your battery connected to your notebook while on AC power. On AC power, the notebook will routinely “top-off” the battery when its charge reaches predetermined levels (i.e. 95%). Removing your laptop battery and storing it in a cool, dry place will help to preserve some of these cycles.