Its not the tuners or the supply to the tuners as I am getting good signal levels reported and 100% quality at all times. The problem would seem to be in the circuitry that does the decoding or the processing of the decoded signals. In the picture that Black Hole kindly posted above, the heat sensitive parts were the chip with the heatsink on, three chips to the left of it, and the one immediately beneath it (partially obscured in the picture by the lower part of the heatsink). The regulators and the SMD capacitors on the main board did not seem sensitive to the hair dryer or freezer spray. I ran out of freezer spray before I could narrow down the culprit further, but if it is one of these chips then any repair would seem to be unlikely.