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I should add that you should never touch the IF adjustment unless you have the proper test equipment or know precisely what you are adjusting.
When completing a video IF alignment of a split sound receiver, I would run a signal through the set and assess the picture when tuned to best sound. I examine the video quality and may slightly improve it (making the video slightly softer or sharper) by ever so slightly adjusting the appropriate stagger tuned IF transformer or coil which most affects the placement of the video carrier on the IF slope. If after adjustment the picture is satisfactory I may just leave it or again re-examine the swept IF response to see precisely where on the slope the carrier is. It may often be best at 40% to 45% instead of the nominal 50%.
However outside of that range if the picture remains soft I begin looking at the peaking coils and detector and Video Amp load resistors. If the resistors have drifted upward, they make the picture soft. The peaking coil may be open leaving only the shunt resistance in circuit. On at least three instances I have found the wrong value peaking coil installed likely due to amistake in manufacture!
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