Sunday, March 24, 2013

Laptop Repurpose

It has been quite a while since I posted last. I have been literally buried by work and during that period that after four plus years of faithful service, my beloved P-7811FX laptop decided to die. The P-7811FX was a loss leader built by Gateway exclusively for Best Buy. It had some bleeding edge features such as DD3 SDRAM, a 17" 16:10 WUXGA screen with a native resolution of 1920 x 1200 and a Labelflash DVD burner. This laptop was priced around  $1200.00, much less than comparable laptops at the time and probably much less than it cost to build. It apparently was only built for a few months and replaced with a new improved model that was actually a step down specification wise.

The problem with it was it had a design flaw which was basically a time bomb. Some of them failed within days or even weeks of being purchased, some like mine lasted much longer. The flaw was in the switching of the GeForce 9800M GTS video card. When the 3D side of the card was not in use and you wanted to play a game with the laptop it had issues switching, this required a software solution that forced the 3D card to work all the time. This created a lot of heat in a card which was notorious for running hot and cooked the motherboard.

This was a problem with nearly all laptops that used the GeForce 9800M GTS and is well documented on many fourms. There are only two fixes for this issue, one is to buy a new motherboard, knowing that it too will die really at anytime. The second was another band aid fix which is "reflowing" the motherboard.

Reflowing is where the solder on the motherboard is briefly melted to allow it to reflow. This fixes the problems created by the video chip overheating and cooling which develops stress cracks and cold solder joints at the chip to motherboard connections. These connections are much to small to solder with an iron.

There are businesses that do this work professionally as it is also a common problem with X-Box 360s. The cost for this service is anywhere from $100.00 - 200.00, with a very limited guarantee for the life of the work. Generally it is done with the following type of equipment which localizes the heat to just the GPU area.

I disassembled the laptop to the motherboard, wrapped all of it in foil except for the GPU and baked it in the oven. Before I did this the laptop would boot up but had a blank display, after reflowing it the laptop worked flawlessly. The problem is like I stated earlier this is a band aid repair and after 1.5 months of use it started to fail again.

Not wanting to discard the laptop due to a failed video card I started searching my options. There are some external video cards but they don't do what I want and aren't a very graceful solution. So I decided to repurpose the laptop parts and started searching for how I could do that. Again the solutions were extremely limited, laptops for one are very proprietary and secondly the mobile architecture they are based on is completely different than a desktop.

In searching for socket "P" motherboards I found that a couple different ones were made, the problem being "were made" as in they are no longer made. They were not common, not popular and very expensive. Finally I found a solution on Ebay in the form of an AOpen i45GMt-HD mini ITX board that was based on the socket "P" Penryn chip.

This board when it was still being built sold for a mere $309.00, I was able to get a new one along with an AOpen case designed for it for less than $70.00. This allowed me to use the 2.26 Core 2 Duo, Centrino wireless card, hard drive and optical drive from the P-7811FX. Unfortunately the board was built around DDR 2 memory so I had to buy some DDR 2 SODIM's.

The neat thing about this computer is its very small, the motherboard is 6"x6", it is completely fanless, the large heatsink came with the motherboard as well as a power brick to meet its 19VDC requirements. When it is on and running it is completely silent. It is able to display HD broadcast TV as well as receive HD radio.

Initially I had planned on putting the motherboard in my car as the basis for a carputer but because of the 19VDC requirements of the board it limited my power supply options. I am going to leave it as it is now and use it as a garage computer / file server.

Here is a shot of the front of it showing the optical drive from the P-7811FX.

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