Power supply is one of the most important components in the computer and of course, the only one, that any other component can’t work without. The quality of power supply is very important for the normal operation of you computer but it’s not responsible about how fast it would be. Therefore, if you replace it with new one, perhaps you won’t feel that you’ve made an upgrade (except that perhaps the new one would be more silent). Very often its importance is overlooked by many users who prefer to invest the money saved from a power supply in more memory, or faster processor.

Typically, a power supply is selected depending on the required power of individual power lines. As you probably know, the main load falls on the 12V line, so exactly the power provided by this line is very important. Many users make mistake taking the maximum values of current provided by any individual power line and multiply them by the voltage to obtain the output power. That is wrong because the 3.3V and 5V as well as different 12V lines are dependent on one another and that’s why in the specifications for +3.3 V, 5V and +12 V is given their combined power.

To determine what power you need you have to calculate the consumption of your computer components. There are many online calculators, which you can use for this purpose, but you should know that there is no such situation in which all components are loaded to their maximum values. For example if you have two hard drives and one optical drive in the worst case you will have two active working devices. Also in 3D games and applications the mainly loaded device will be the video card, unlike the CPU which will be away from its maximum load. It is also possible the opposite situation, where the processor performs havy calculations, while the video card stays almost unused. Typically, the actual values are about 75-80% of those made by such calculators, but if you add additional capacity for future upgrades, the values calculated in such a way would be quite normal. For a modern computer, as a minimum can be considered values of approximately 350W.

The next thing that you should pay attention to, when purchasing a new power supply is the energy efficiency. The higher values mean that your power supply will convert the voltage from the electrical network more effectively and of course it will produce less heat and noise. Most widely used power supplies have an energy efficiency ratio of about 70-75% but higher-quality power supplies can be over 80% efficient.

Most power supplies are equipped with 80mm or 120mm cooling fans. Larger fans recommended because of the small amount of noise they produce compared with the 80mm fans. There are also the so-called “completely silent” models without fans. They have specially designed cooling system with high efficiency, but are usually considerably more expensive and their power is limited to about 300W – 500W.

Another important requirement for the power supply is to have a sufficient number of connectors, which can save you a lot of problems when adding new hardware. There are also Modular Power Supply Units in which the users can modify the power connectors to suit their personal needs. Unlike the conventional design where power cables are permanently connected to the power supply, a modular power supply provides an option allowing unused cables to be detached from it. By allowing cables to be detached, modular cabling can help you not only to reduce the clutter of unused cables but also improve the airflow within the case.

The first and maybe most important thing to know is that no matter how trying to save the life of your battery, sooner or later you will need to replace it with new one. You should also know that today’s technology still doesn’t allow the production of durable batteries whose characteristics do not change over time. Manufacturers of batteries use different innovations to reduce the effects of the negative aspects of technology used to produce this type of batteries, but generally, lithium-ion batteries have some unavoidable shortcomings that limit their lives within a maximum of about 2-3 years. This is the normal period of use, after which you can use only part of the initial capacity of the battery.

Typically, manufacturers provide between 6 months and 1 year warranty for batteries, that includes their normal operation, but doesn’t refer to the reduction of the working time of a battery due to its wear and reduced capacity because these factors are highly dependent on how the battery is used. In addition – in the cheapest laptops you will not find the best quality batteries, because the manufacturers’ choice of batteries depends mostly on the  cost of final product. You should also know that the quality assessment of the batteries is impossible without special laboratory equipment, so it is advisable to choose batteries with a longer warranty.
If you travel frequently and you have to use your laptop mainly for work on battery, my advice is to always have a spare battery, with a higher capacity (if possible). It should be noted that finding batteries for brands like HP, Toshiba, Lenovo and Dell is relatively easy because these manufacturers have established themselves as leaders in the production of mobile computers and already have authorized service centers and stores worldwide. In fact, except at the official distributors, batteries for almost all brands of laptops can be found at ebay. The good news is that there you can find non-original batteries (these are not produced by the manufacturer of your laptop) as very often their price is times lower than the original price of batteries offered by distributors. Of course, this doesn’t apply to the specialized batteries that are found in most expensive laptops but I think it makes no sense to pay over $ 100 for a “regular” battery, as there will be hardly a difference in the quality of the original and non-original batteries in most cheaper notebooks.

Capacity of the Li-Ion Battery.

In most cases, the battery capacity indicated by the manufacturer is very different from what Windows, or any standard software can see and use. According to Windows, 0% of capacity, actually means that the battery has a minimum balance of energy which is necessary to be maintained, because otherwise it will stop functioning. My advice is to not store batteries with such a minimum charge for a longer period of time, because there is a real danger that the battery could be discharged completely, and this can be fatal for it. The maximum capacity is theoretical and it will change over the time – it’s an inevitable part of aging of the battery, but its effects can be minimized. Moreover, the maximum capacity generally ranges – i.e. battery with capacity of 4200 mAh could easily be over 4500, but may be 4000 mAh. Of course this can not be measured in advance and is a result of the production technology of these batteries.

Working conditions.

Lithium-ion batteries do not like high temperatures. If the battery operates at 0 degrees celsius, the discharge time will be longer than if it operates at higher temperatures, but at 0 degrees will be difficult to charge the battery. Temperatures over 80 degrees are  potentially dangerous not only for the battery, but also for the device powered by it. Operating temperature is important because these batteries produce heat when discharging (i.e. when used), which increases their internal resistance and reduces the output voltage. This process accelerates the discharging of the battery, leading to a reduction of its working time. In laptop, batteries are usually located at the bottom of the device near heat sources, which makes their cooling a little more difficult.

Li-Ion batteries are strongly influenced by the ’strength’ of consumption ( i.e. the rapid discharging caused by high load shortens the time to work). Therefore, manufacturers use batteries with more cells, because the speed of increase of their internal resistance is less than the speed at which this happens to batteries with a smaller number of cells.

It is more practical to use your laptop in power saving mode not only because it will work longer due to decreased energy consumption, but also because of reduced power requirements – more intensive use of the CPU greatly reduces the time on battery. This means that it is not a good idea to play games while running on battery because the laptop thus consumes more power and the stored energy is going faster.

Storage method of Li-Ion Batteries.

Lithium-ion batteries have very low self-discharge rate – this means that under ideal conditions, battery charge decreases very slowly until exhausted. This self-discharge depends on the ambient temperature and is lowest at lower temperatures. It also depends on the level of charge which means that if the battery is fully charged, its self-discharge rate will be higher. The experts recommend a level of charge for storage of approximately 40% and storage at temperatures below 10 degrees.

Recharging Li-Ion batteries.

Unlike other types of batteries, where every charge ( regardless of how much charge is in the battery ) is called a”cycle”, because of the way of charging in lithium-ion batteries, a “cycle” means the sum of charges, during which the battery charge has reached its total capacity. This means that whatever the level of charge, one “cycle” will be made only after the battery was discharged and after that recharged to a total of 100% of its capacity. In other words, every recharge by itself does not represent a complete cycle. The sum of these charges, which form a 100% charge, may be identified as a “cycle”. Recharging is also important for the battery life duration, because it should be performed in several stages, which are sometimes skipped by manufacturers in order to accelerate the process, by using higher voltage during the charge. This does not concern you, as ordinary user, because typically you can not control it – the laptop manages the voltages for charging by itself.
Unlike old NiCd or NiMH batteries, Li-Ion batteries do not suffer from the “memory” effect, that limits their maximum capacity. As you probably know to eliminate this effect manufacturers recommend an occasional, complete discharge of NiMH batteries followed by a full recharge. Fortunately this doesn’t apply to the lithium-ion batteries. This advantage, along with the reduced weight and better capacity, is one of their main advantages, which makes them relatively easy to use, especially in devices like laptops and phones, where you have no control over the recharging process. Anyway, I think it is almost impossible to completely discharge your battery, because Windows will usually indicate that the charge is running low when its value reaches 10% and computer will be shut down upon reaching the 5% charge in order to avoid any loss of information. However, you will not lose anything if you perform the above recharging process every 2 months.

This guide explains how to clean the cooling module and apply new thermal grease on CPU in Aser Aspire 3515 series laptop, but most likely this guide will also work for some other Aser Aspire models. In this model you first have to remove the CPU fan and then remove the cooler ( heatsink ).

Remove cooling fan.

1. Remove four screws marked on the picture below.

2. Remove three screws securing the fan and disconnect fan cable from motherboard.

3. Remove the fan.

As you can see the heatsink is clogged with dust, which stops the air flow passing through it. For cleaning  I  suggest using compressed air.

Applying new thermal grease on CPU.

1.To apply new grease you have to remove four screws securing heatsink to the chassis.

2. Now carefully lift up the heatsink.

As you probably know thermal grease (or thermal compound ) helps for the better conducting of heat between the CPU and heatsink. In this laptop the heatsink covers both the CPU and video chips.  The video uses thermal pad to conduct heat to the heatsink and that’s why you will find thermal grease only on the CPU. If it looks dry, you’ll have to replace it with new grease, but in this case you first have to clean the rests of thermal compound that remain on the CPU and heatsink. I would suggest using soft cloth dampened with alcohol or acetone.

Now when both surfaces – of processor and cooler are clean you can apply a thin layer of new thermal grease on the CPU chip (black part).

It has to be thick enough ( but not too thin ) to ensure that the heatsink and CPU are in good contact. Next, carefully install the heatsink over the processor and tighten four screws.

This guide will help you to remove and replace the keyboard in a Packard Bell MX37 series laptop, but most likely this guide will also work for some other Packard Bell models.

CAUTION: Before you begin any of the following procedures, turn off the laptop , unplug the power adapter and remove the battery. Note that computer parts are very sensitive to static electricity so ground yourself before touching anything inside you computer by using grounding strap or touch a metal faucet  pipe.

1.Remove all marked screws securing RAM, CPU and WLAN cover.

2.Remove four screws securing the keyboard.

3.There are four latches on the top of the keyboard. Using small flat screwdriver press each of the latches down until the keyboard is released.

4.Carefully insert small screwdriver between the top side of the keyboard and notebook case and lift up the keyboard. Be careful with the ribbon cable because it is very short and any possible damage would mean buying a new keyboard.

5.Place the keyboard upside down so you can access the cable connector underneath.

6. As you can see the keyboard cable is plugged into the connector on the motherboard so you’ll have to unlock the connector before removing the cable.  On the picture below the cable connector is shown in locked position.

On the following picture, the same connector is shown in unlocked position.

7. Now you can pull the keyboard cable from the connector and remove the keyboard.

8. When installing the new keyboard align the five securing tabs on the front of the keyboard with the slots on the upper case.

9. Ensure that all five keyboard securing tabs are engaged in their respective slots and press the down on each of the four latches until you hear a clicking which means that they are locked.