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How’d They Make That 2 May 11, 2009

Posted by laptoppartsexpert in AC Adapter, DC Jack.
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After discussing the makeup of a battery, I thought I would do the same with AC Adapters. Unlike batteries, AC Adapters are very straightforward in that there are only a few different types. Usually, you will see a fixed voltage of 15V, 16V, 19V, 20V or 24V. Sure, there are a few odd ones like 15.6V for Panasonic or 18.5V for some Compaq/HP or 19.5V for Dell or Sony. The formula for AC power is simple:

Voltage x Amperage = Wattage

Now, let’s talk about why this is important. You must use an adapter with your laptop or netbook that is +/- 1V from the recommended voltage on your unit. In addition, the minimum amperage required for the laptop to get power at the specified voltage is the amperage the laptop will pull from the adapter. For example, if you have a laptop that is 19V, 3.42A, a 65W requirement, and you use the corresponding adapter, the laptop will get the power that it needs. If you use a 90W, 19V, 4.7A, the laptop will pull 3.42A of the 4.7A available. There are some manufacturers like Acer that offer the 90W because they say it is a rapid charger for the battery. Other manufacturers like Toshiba offer a 90W adapter because they have sold out of the older 75W version. However, if you have a 90W laptop that requires 4.7A of power and you only give it 3.42A, the laptop will pull 4.7A out of the available 3.42A and the adapter will burn up over time.

Over the years, I have seen HP ship a 90W adapter for a laptop that needs a 135W and the result is a bad adapter after a few months. Some laptops have a safety feature that will not allow the laptop to turn on if it does not have the proper power available.

The next step in matching an adapter is to confirm the polarity of the tip, usually center positive and match the pin size of the adapter to the DC Jack you plug it into. It is important to note that since DC Jacks have become available, many people have replaced jacks that have the same footprint as the old jack but have a different size center pin. This means that you may try to get a replacement adapter that will not match. In this case, you have to measure the pin size to get a match.

One more warning. If you have get a universal adapter, you need to make sure it has a fixed voltage for your laptop. Many of the major brand universal adapters go from 15V-24V and have a tip that regulates the voltage based on the laptop you are plugging it into. However, if the tip goes bad, you end up with 24V shooting into your laptop which will do major damage to your laptop. If you need an adapter custom made and you have the voltage, amperage, polarity and pin size, we can usually have it made in a couple days. You can email us at info@laptoppartsexpert.com.


Tear It Down May 5, 2009

Posted by laptoppartsexpert in Disassembly, Optical drive.
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1 comment so far

A customer emailed me today looking for a DVD drive for his Toshiba Satellite P25 laptop. Unfortunately, Toshiba sells many drives for this model and they all use a different front plastic faces while using the same backplane and bracket. Also, they offered a DVD, a combo drive and a DVD-RAM. You have to match the old drive or you will have to buy a new face for the replacement.

The customer did not specify so I told them they would have to give me the core part number on the drive to get the right one. There are two ways of doing this. The first, is to go to the Windows Device manager and check the DVD/CD category. The second is to take out the drive and look on the label. The customer however, did not know how to take it apart. So, for any of you that need to disassemble your Toshiba, I recommend teardown guides at our advertising partners’ website, IrisVista.com/Tech. These sites are specifically for Toshiba. You can find guides for other brands on the resources page of our website, http://www.laptoppartsexpert.com/p-159-resources.html.