The heatsinks I found at Rat Shack are for bolting onto TO-220 devices. The smaller one is just a hunk of extruded aluminum cut into blocks (276-1368, $1.69 ea.) These are very light weight but probably have more thermal mass vs. the stamped ones. I think these would work well. My plan is to mount two of them to the 7038 with a small space in between with the fins aligned R/L. This would cover about 75% of the chip's surface. The grease itself will be enough to hold them in place as long as the unit is not turned-over, but I'll probably tack them down with a tiny spot of glue on each corner, maybe hot melt. Then I'll probably mount the fan vertically, probably to the right side of the chip with the air blowing to the left towards the PS, maybe by using some 2-sided tape on the board. That will put it underneath the HDD bracket and give me something to work with in terms of a better mount from above. I might even find a way to just suspend it from that bracket so it doesn't even touch the board, but I think I am more interested in blowing the air from the right to the left across the chip/heat sinks vs downward like most CPU coolers, so I need to mount it accordingly. That will also help get some air moving across the demodulator chips to the right that also run very hot. (I may eventually give them heat sinks as well, maybe the same ones.) One goal for me is that everything is "reversible", i.e., I can remove it all with no evidence that it was ever there. (Wonder why ??)
The space between the sinks is to allow me to leave the thermocouple in the same central place throughout the experiment. I'll "mount" it there with some grease to start and redo my readings. (IIRC, the center of the chip is NOT the hottest part!!), then repeat with just the sinks, then repeat with the fan blowing. I think that will show some significant improvement!
I will do nothing to the stock fan in case it ever gets called into action, but I figure the other measures I'm taking will ensure it a very modest assignment for the life of the unit!
More to come...
(Gee, I just love these little "design on the fly" projects! Great to 'talk' them through with others that share an interest in the outcome...!)