Here is the schematic of the solution I finally settled on:
As you see in the schematic, I have decided to go with a two-position switch. This provides me with an auto fan speed or 100% fan speed depending on switch position.
Here is the mod I had already previously done to the laptop fan:
The mod consisted of simply soldering a 17kΩ resistor in series with the tachometer sense wire. I removed my
previous mod and then connected the tachometer sense wire to a breadboard to do some testing.
Once done testing, I soldered it up onto a little circuit board.
Notice how I used shrink tubing as much as possible to keep the mod "clean" looking. Then, I applied a bit of
liquid tape to the finished soldering job in order to protect the circuitry from the conductive laptop access
panel you will see in a bit.
Here is the inside of the access panel. You see that it has a conductive coating applied to it which is
designed to reflect heat. I didn't want my fan tachometer wiring to short to ground. I cut one of the slots
larger to fit the switch through the slot.
Then, I had to come up with some way to attach the switch to the panel. I decided that I would tether the
circuit board to the access panel with wire. Here I have attached two anchor wires to the circuit board.
Then, I inserted the switch through the slot, passed the anchor wires around the other side of the access
panel, and then soldered the anchor wires back to the circuit board to hold it in place.
Finally, I applied a little sealant over the top to help secure the circuit board in place and make it blend
in better with the access panel.
And now for some results! Pay little attention to the poor image quality you see in the DiRT 2 game window. I
normally play the game full screen and just windowed the game for each screenshot so that RealTemp could be
viewed. For some reason, while in windowed mode, the game looks horrible.
Anyways... Here are the auto fan speed versus 100% fan speed comparisons.
Auto (default):
100%:
As you see, video card loaded maximum temperature dropped by 4°C. It is also worth noting that while DiRT 2
certainly isn't a CPU stress test program, in this instance, maximum CPU temperature dropped 0-3°C as well.
This is most likely due to the fact that the laptop only has one fan and that fan cools both the CPU and GPU.
EDIT: I achieved a further 6*C drop in GPU temperature by switching my GPU thermal paste out from Arctic Silver 5 to IC Diamond.
post edited by ty_ger07 - 2011/03/10 23:36:33