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on thing I learned is the test equipment itself can mess up the curve. I had an ill shaped hump, turned out to be the clip on the TP was close the the IF coil, it made a HUGE diff just moving that clip around. Tubes effect it as well. One time it turned out to be an intermittant IF coil connection (prob due to all my fiddling). Considering the RF freq are so much higher than the IF, there is no way I would get near the tuner for alingment, not really needed anymore do the the lack of OTA analog signals, most of my watching is on channel 2 or 3 whcih ever works better.
I really wanted to do an IF alignment just to see how it works and I like to learn new stuff, from that exp I learned to respect IF aliignment but not fear it. Still I would only do if if all else checked ok AND the sweep proved a problem as is AND I was pretty darn sure I had the hookups right.
What I found very helpful was to hook up to another chassis (hopefully the same model) that is working well and sweep that. That a good way to validate the hookup and how it should look. What I found was while the waveforms were sorta like they should be, they were by no means perfect looking yet the picture was fine.
From this I deduce, the IF curve was not as critical as I thought (at least on a B&W set) or my connections were impacting the curve. I suspect the latter since minor repositioning woudl alter the results. I tried to get the wave as near as possible on the working set, noted the cable setups, then returned to the non working set (after I goofed it up) did the exact same deal with lots of care on lead dress, and then lots of patiencd on AGC bias and RF power to get the hump to not clip. I ended up with less gain but better looking bandwidth. The result was a near perfect pic that look pretty much the same as a direct feed of the composite signal at the post detector TP.
Which brings up a second point, I would recommend you do a composite video feed directly at that TP. that would isolate the issue to before or after the IF section.
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