The H20 only has 1 satellite tuner. You must be talking about the HR-20.Just a note about the 498,73,73,498 sequence for checking both tuners on H20. The channels you change to are irrelevant other than 498. Each time you change channels , you change tuners:
for Example
498 -Tuner 1
CH x -Tuner 2
CH y -Tuner 1
498 -Tuner 2
So you've tested both tuner 1 & tuner 2. x & y can be anything and simplest sequence is:
498 -One tuner
CH+-Other Tuner
CH+-Back to original tuner
498-Now testing 2nd tuner.