Ok. Let’s try this again…RCA 9TC240 Alignment

[Penthode]

Originally Posted by Chris K

Symmetrical it is but it does not look exactly like the trace in the service information. Don't want to mislead anyone. I don't have all of the signal trace in figure 13 but what's missing from it is the same from the positive end to the negative end. I don't get the first or last 20% of the trace but what I do get on the scope is centered and symmetrical. Putting 21.25mc on the origin (X=0, Y=0) and the appropriate markers on the sweep, they are all symmetrical with respect to zero and almost straight between 21.17 and 21.32 with 21.25mc at the midpoint. IDK if that makes any sense but I'm pretty sure this is OK given what you've said about the relative swings of voltage above and below the midpoint (21.25)

Did you try increasing the sweep width on the 8601a generator? It appears that the sweep width is too narrow. Once you have the sweep width wide enough to see the s curve, you can use the adjustable markers to ensure you have the 350kHz between peaks. This is very important.