Vertical Line - Raytheon Porthole 1602

[Electronic M]

VA62s are not exactly proper alignment equipment either...In the conventional sense. Supposedly there are ways of aligning and psuedo-aligning with one, but I have not heard a convincing explanation or seen a good demonstration.

[cwmoser]

How are these older Televisions that use the old IF frequencies aligned using the test equipment we have today?

[Electronic M]

Some of the newer (SS) Sweep marker generators had provisions for the older IF frequencies. You either find newer gear that works or fix older gear. Alignment generally consisted of setting up sweep/marker injection somewhere around the tuner, and placing a demodulator probe connected to the scope vertical channel near the detector stage. The scope H channel would be connected to the sweep generator sweep rate signal. You would get a band-pass response curve on the scope. You would switch on markers of specific frequencies to adjust traps and to see if peaks, valleys etc were in the right places, and tweak slugs to move them and shape the curve to meet the spec...Each set's service literature should contain detailed instructions outlining the procedure and response curve desired.

I've never done TV alignment, but I know that video IF alignment is supposed to be a substantial chore....I've got some sets that need an alignment, and have been collecting gear in preparation, but I need to check the calibration of my gear, read up on the procedure, and find a set I don't care about to practice on before I seriously get into doing full alignments.

[Kevin Kuehn]

If you want to learn TV sweep alignment it's best to get some old servicing text books, or a sweep alignment generator operators manual that explains the process. But before go there you need to have a fairly solid understanding of how the video and audio signals travel through the various circuits. Without that basic understanding you're really at a loss as to how the equipment gets connected into circuit and what you're actually looking at on the scope display.

I had TV servicing classes back in the early 1980's and I don't recall us ever doing video IF alignment. I do recall our textbook for that class had an endorsement on the Sencor visual alignment process, but it never went into any detail on a practical way to utilize it. Even the manual for those units seems to tip toe around that specific application. IMO those units are more less a bells and whistles version of a video test pattern(to see what the video IF response of the set in question looks like), but not so friendly when it comes to adjusting the video response curve.