Last week we had a customer who was experiencing some distorted video on his 30″ LCD computer monitor, a Samsung Syncmaster 305T. When I had a look for myself, I noticed that lighter parts of the screen, whites especially, were taking on a green tint with random vertical lines. Having seen something very similar before on a Gateway XHD3000 30″ LCD monitor, I judged the issue to be a faulty video conversion chipset. When I dismantled the LCD, and took a look at the internal hardware, I was very surprised at what I found. Apparently the Samsung 305T is the EXACT SAME monitor as the Gateway XHD3000, with a different casing and branding. Who’da thunk’it?
After doing a standard reflow on the main video chip, the issues with the monitor ceased, further confirming that this model suffered from the same issues the Gateway version did. While testing I decided to test out the temps the chip was generating. Turns out that the main video chip was sitting at between 90°-102°C most of the time if left on for more than 30 minutes or so. No big wonder why it fails so often. Due to this, we decided to rig up a cooling system for our customer to keep his $1200 monitor from burning out before it’s time.
We chose a Thermaltake Spirit A100 chipset cooler to accomplish the task, mainly because it was the perfect size to fit the chip’s dimensions exactly, and also would blend in nicely with the rest of the casing (other than the bright blue lights)
First thing we did was to wire the fan up to a USB cable (since this LCD has onboard USB ports) from which to pull voltage. All of the LCD’s internal voltages were far too high to hook up a bitty 40mm fan to, so instead we opted for a non-invasive low-voltage approach instead.
Tt Spirit A100 all wired up and ready to go
Next we had to cut a hole in the case the proper size for the fan and heatsink to rest on the chipset. I used a standard dremel rotary tool with a carbon fiber cutter wheel to do the job. First I measured out the dimensions of thecooler, and using the measurement and ruler pretty much just eyeballed the first cut over the chipset. I made sure to make the first cut a little too small so that I would be able to gauge the next cuts better by replacing the case over the chipset and re-measuring. By this method of cut, re-measure and cut again I was able to get a hole perfectly sized and positioned for the fan and heatsink:
Finished hole for the Fan and Heatsink
One thing I did not know about when we bought the Spirit A100 is that the blue color is on the base as well as everything else, so I decided it would be a good idea to Lap the base. I discovered it was a good idea to do anyway as the base was slightly concave and would have needed lapping anyway for perfect contact I didn’t bother doing a mirror finish job, since what I’m attaching it to is basically just a shield over a silicon pad on the chip itself:
Lapped using a glass coaster and 800 grit sandpaper
After the lapping was done successfully, all that was left was getting the chipset in place and permanently mounted. To accomplish this we chose Arctic Silver Thermal Adhesive (not Arctic Silver Thermal Paste), which works like other epoxy in that it has two parts that are mixed and takes about 15 minutes to cure. I set the chipset with the back casing on to make sure the fan was positioned perfectly:
Positioning the chipset for the adhesive
A perfect fit! Fan was even flush with the higher section!
To be sure we could go back later to make other adjustments, repairs, or what-have-you, I made sure to paste the heatsink onto the main video board’s RF shield, and not directly to the chipset. While this will hinder thermal performance somewhat, It will allow for error correction later on or re-repair of the board, and I figured this chip would be kept cool enough just to have some active cooling rather than nothing.
Heatsink after thermal adhesive has set
Turned out that having the chipset fan made a huge difference to the video board. While testing, the video chip never got above 50°C, cutting the original operating temperatures in half! It should be noted that we DID turn the AC on halfway through the installation, which could have fudged the temperature variance some, but it appears to have done the trick! Another happy customer!
Doing its job marvellously!
Can hardly see the chipset heatsink! Fan sticks out a bit though 
