Reworking The Installation
We’ve already proven that we’re not afraid to risk a little “free hardware” to prove a point, and we’re completely familiar with methods that would have prevented condensation from accumulating in fragile areas. These methods include painting the entire board with nonconductive sealant, sealing the entire area around the CPU with nonconductive putty such as kneaded eraser, and filling the LGA with dielectric grease. Unfortunately, most of these solutions cannot be completely removed from the motherboard. While we only needed our system to run for 12-hour intervals, we do recommend most of these precautions for extended use.
The one drop of water that stopped the system had left a trail, starting at the evaporator and running past the round hole in the foam barrier, down the side of our CPU socket, and into the Land Grid Array (LGA). Nonconductive putty was added to fill the gap between the CPU’s heat spreader and socket’s pressure plate.
A new layer of tape seals the CPU area to the reinstalled, custom-cut foam layers. The foam sheet with the round hole was reinstalled over this tape.
A bead of putty fills the space between the evaporator’s mounting block and top foam sheet. These minor changes allowed our system to run eight, but not the full twelve hours between dry-offs.
Removing the CPU after an eight-hour test session revealed drops of condensation on each of its 1366 contact pads. Air circulating under the CPU was the problem, and that problem can be solved by filling the LGA with dielectric grease. Petroleum jelly makes an adequate substitute for dielectric grease when used at moderate to low temperatures, such as those experienced with sub-ambient CPU cooling systems.
As seen in our 2008 Overdrive Competition, applying putty around the CPU socket is another option to further prevent air from getting underneath it. Unfortunately, voltage regulator chokes immediately adjacent to the socket of the motherboard we used today would have severely obstructed such work.
