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Old 09-20-2016, 12:48 PM
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DavGoodlin DavGoodlin is offline
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CTC-16 trap alignment

Where is the "3.58 MHz trap" referred to by the Sencore Manual? Nowhere on 736 schematic sams or in the RCA booklet is it labeled.

Is this the non-tunable LC network between the 1st and 2nd video stages?

The Sencore VA-48 and the bar sweep function allows checking of trap settings. By reducing brightness/contrast, several bars are supposed to disappear from the raster in order.

The first to extinguish should be the 3.56 mc response bar, but it remains brighter as others like 4.08mc drop out, the manual says this means the 3.58 MHz trap is not peaked.

I can confirm this because a color or BW picture has picture has horizontal streaks that cannot be removed by adjusting fine tuning but I also may be seeing 4.5mhz trap in the video stage.
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Old 09-21-2016, 02:07 PM
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DavGoodlin DavGoodlin is offline
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What does not make sense is the traps for sound reject (pot after 3rd IF), adjacent sound reject (pot before 1st IF) and the 4.5 mc trap coil 1st video after the sound take-off seemed to make matters worse when set using the generator.

Is a VA 48 too new of alignment instrument for this TV? Maybe its easier to fire up the old sweep generator, hook up a scope rather than watch the screen?
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