The old diode looks open (infinite resistance both ways), using either the ohmmeter or the diode check function on my meter. Don't ask me how it was able to pass any signal at all in that condition, but perhaps I torched it during removal, and it worked in some half-baked way before.
Maybe someone can help me make sense of the demodulator adjustment procedure in the RCA manual, which I posted here:
http://antiqueradio.org/art/temp/RCA...dProcedure.jpg
Question 1. It seems like the writer got some colors jumbled:
-- Step 1 tells you to short the blue and green control grids to ground through 100K resistors.
-- Step 3 tells you to remove the 100K resistor from the red grid -- but no resistor was ever placed on that grid -- and then place it the green grid -- which already has a 100K resistor from Step 1.
-- Step 5 tells you to remove the resistors from the red and green grids.
Huh??
One way to make sense of the instructions might be to amend Step 3 to say, "Remove 100K resistor from BLUE control grid and place it between RED control grid and ground." That would leave you with resistors on the red and green grids, which allows Step 5 to make sense.
Question 2. Unfortunately, I don't have a pattern generator that can make the same color bars as their example, so I'm not sure what is meant by an instruction like, "Adjust L125 until the sixth color bar (blue) blends with the background." What color is the "background" of that pattern generator? Black? White? Other?
Adjusting L125 and T115 (top) per those instructions changes the bar hues, but the question is how to do this with my newer pattern generators that produce bars with the usual sequence of white-yellow-cyan-green-magenta-red-blue-black.
An alternate phasing adjustment procedure with oscilloscope is described on page 49-51 of the
service clinic manual, but the same question applies -- what waveforms to look for when using the different (i.e., modern) color bar pattern. Perhaps if I stare at Fig. 96 on page 49 long enough, I can draw my own diagram and model waveforms . . . .
Phil Nelson