I will keep plugging along. On the positive side, I tried dtvmcdonald's trick to test the crystals, and they all look good, including the one that was installed in the set. Each of them shows a distinct peak on the scope at around 3.58mc.
I replaced a couple more components around that tube, without making any improvement. This updated schematic shows the 5 caps and resistors replaced there.
None of those components was grievously out of spec -- well, R249 measured 54K instead of 47K -- but at least I can cross those off the list of possible suspects.
Of the remaining components connected immediately to that tube, we also can eliminate the crystal, which tested OK, and resistor R248, which measures a hair over 47K.
Edit: I just saw the reply from Zenith6S321. One thing I haven't tried yet is disconnecting L42 to measure it. I can try that later on, along with giving the socket another good hard cleaning.
Phil Nelson
04-09-2015, 06:30 PM
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