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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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4 comments

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.

Compaq/HP Screen Help May 8, 2009

Posted by laptoppartsexpert in LCD.
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2 comments

Got a call today that I have not received in a while. But, if you have an old Compaq of HP laptop, this may be of some interest to you. Until about two years ago, Compaq and HP almost never offered screen parts for their laptops. That meant hinges, cables and plastics were not replaceable. There can be a way around this. If you have the Compaq or HP spares number or SPS number for the LCD, you can use this number to search for people that have torn down a whole laptop and are selling the spare parts under this number.

For example, my customer was looking for a hinges for an HP Pavilion ZV6233CL. This particular model uses a screen part number 383939-001. I was able to find the hinges under part number 383939-001-HINGES. This will not work with every model, but it is one more avenue to search for that part you are looking for. If you would like me to research your Compaq or HP part, email me at jeremy@laptoppartsexpert.com.

How’d They Make That May 5, 2009

Posted by laptoppartsexpert in Battery.
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4 comments

I seem to have caught HP in a math mistake today. Now if you aren’t impressed by math, this may not interest you. But I will attempt to pull back the curtain on what makes a battery rated for the capacity it is rated and why it is important to know the rating of a battery before you buy one. This is the listing on the HP website that was presented to me:

Battery (Primary) – 6-cell lithium-ion (Li-Ion), 14.4VDC, 2.20Ah, 47Wh

This is a Compaq/HP Business Notebook battery and it just doesn’t add up. See, every battery has voltage cells and amperage cells. The voltage cells are usually 3.7V and the amperage cells range from 2200mah up to 2600mAh in capacity. Most batteries are 11.1V or 14.8V and 4800mAh or 5200mAh. If you put three voltage cells together and two amperage cells together, you get a 6-cell battery. If you put four voltage cells and two amperage cells together, you get an 8-cell battery. Simple math, for example:

3.7V X 3 = 11.1V
2200mAh X 2 = 4400mAh
3V X 2A = 6-cell

This is the 6-cell version of the above mentioned battery I sell. But HP lists this as 14.8V (4V) and 2200mAh (1A) which makes it a 4-cell battery. As our former President might have said, “This is fuzzy math.”

Now, lets talk about why this is important. We all want our laptops to run as long as possible but battery life is limited. Typically Lithium batteries, the current standard, are good for about 300-500 charges. They work best when you charge them up, drain them down and repeat at least once per week. They can also run longer if you lower your screen brightness and lower your hard drive spin time. But the higher the cell count, the bigger the battery, the longer the laptop will run on a single charge. Of course they get heavier the longer they last, but who cares, you want to finish that long Martin Scorsese epic. If you want a good battery, you want an 8-cell minimum. If you want the biggest battery, you need a 12-cell, if offered for your model. I am only aware of one 16-cell but that is for the mammoth Dell Inspiron 9100/XPS. You also want to make sure you are getting a higher amperage rating because they will be newer cells. You want something divisible by 2400mAh or 2600mAh.

One more equation for you. If you know the Watt-Hour rating of the battery, a new labeling requirement, you can get the amperage rating by dividing the Watt-Hour rating by the voltage. For example:

48Wh / 11.1V = 4400mAh

This is the rating of the battery above. Ultimately, the higher the battery Watt-Hour rating, the longer it will last between charges. If you have any questions about battery ratings or you want to tell me I finally made math interesting for you, you can email me at info@laptoppartsexpert.com.