I, too, picked up a pressure tester off eBay ($170) and, as an aside, a Timegrapher as well. I use them to test the new stuff I buy and test again before I sell for full disclosure to prospective buyers.
Very lightly "greasing" gaskets with silicone helps. If water gets in anyway, and you see condensation under the crystal after leaving ice against it a few seconds (primitive but works) pop the back off, put a dust free cloth over the movement, and dry it off under an articulating desk lamp. Re-grease the seals, test it again and go back in the water.
Obviously if you have salt water in there, you have an issue of greater concern. ;-)
As to the HEV its a source of water infiltration on models I've had. A dot of West Systems epoxy thinned with acetone and applied with a toothpick will fix that right up.