[Penthode]

Further examination of the tuner revealed a second 1000pF capacitor physically separated and open. This bypasses to ground the 6AF4 local oscillator plate return: if it is open, it would likely reduce the oscillator amplitude a frequency marginally.

The third chassis mount 1000pF capacitor looked solid. I noticed the color was green as opposed to the amber faulty ones. Perhaps it was a different batch.

Anyhow, to summarize, it has been essential to run though the RF/IF alignment for any set as the problems would snowball. Besides affecting the luma response by introducing smearing and ringing in the picture, it would drastically affect the I and Q channel responses I plan to examine when I am done the front end.

Proper RF/IF alignment clearly differentiates between the construction costs between late forties RCA sets. Comparing the 721TS which has three IF stages, with an 8T243 or the 8T270 with four IF stages, a proper alignment reveal extra picture detail on later sets. You see the extra detail on the resolution wedge which may be resolved to the center of the pattern and the 721TS ther esolution wedge extending only 2/3 the way down. In this color set which has the the added complication of not only color but the separate chroma difference channel paths.

So this exercise I feel shall be justified by the results i will later find.