Reflow Soldering Toshiba 5105-s701 geforce 440go graphics chip

[foolishfish]

I got a toshiba 5105 series laptop in for repair last week. I was told it suddenly started showing lines down the display, so I gave it a once over.
Sure enough, it was doing what the client stated.
After a google search for Toshiba 5105 graphics issues, it became clear that this was a known issue with thousands of these laptops.
A little more reading revealed that toshiba's bga soldering wasn't holding up, with some laptops only lasting a few months and others going bad only after years of use. This particular laptop lasted over five years, so no chance of an in warranty fix.

After removing the keyboard and pressing directly on the laptops video card to verify that the graphics cleared up when contact was made between the video chip and the pc board it's attached to, I then set about disassembling the laptop to *attempt* repair.

Disassembly was easy, much easier than most laptops. Once the video card was extracted, I decided on a course of action.
With the Apple laptops that had similar issues, people were putting alcohol in a small metal cap and burning it to reflow the solder, but that's just a little too primitive for my tastes.

Instead, I found another video that showed an uuber geek removing and resoldering a bga chip.
I didn't go as far as he did and remove, desolder, reball and replace, but I did find his use of aluminum foil for a heat shield to be interesting and useful.
Using a foil heat shield, I set my heatgun on low and heated up the Graphics and memory chips on the card to the point when the solder melted and then let them cool for about a half hour.
Then I reassembled the laptop and turned it on.

Success!

Something new for my bag of tricks!!

[Mender]

I've resoldered dry connections on many surface mount chips in the past. Some of those chips had pins just 0.2mm wide, with the spaces between them 0.1mm wide - not a lot of room to solder individual legs. I managed to solder them using a modified soldering bit on my variable heat soldering station. The bit was bought off the shelf with a pointed end on it, the thickness of the point was 0.2mm, just right for the modification. I drilled a hole 0.15mm through the point to about half way through the bit. Then I drilled a 3mm hole in the side of the bit, about half way along and half way through, to meet up with the first hole. I had a short length of copper rod, 3mm diameter which I drilled a 1.5mm hole right through the centre, then forced one end into the 3mm hole. A length of heatproof silicon tubing was pushed onto the open end.

I put a clamp on the tubing near the soldering bit to stop air entering. Then I turned the iron on at maximum temperature. When it reached the max heat. I pointed it upwards and applied a small amount of multicore solder to the tip. The solder sucked itself into the little hole. Then I turned the iron the right way up, removed the clamp, put the open end of silicon tubing between my lips, and applied the tip of the iron to where the offending leg of the chip touched the solder pad on the board. After about two seconds, I breathed gently into the end of the tube, and the tiny bit of solder in the hole was forced out by the pressure to where the leg rested on the solder pad. I immediately removed the iron, and checked the leg was firmly attached to the board.

I never had a failure using this method, and it earned me quite a bit of money over several years, as nobody else in the area had the facility to do this sort of job.

 

[foolishfish]

Nice!
My hands aren't steady enough for that kind of job, I'm lucky I can hold a heatgun

[fxcapt]

Fishy, as you stated, that lappy isn't as bad as some are to work on.  http://www.irisvista.com/tech/laptops/Toshiba5105/satellite_5105_vga_remove_1.htm. I have a Dell with a bad DC jack to replace, and thats a breeze compared to what Roger has going. I would never attempt that little magic trick.