Schematic for Westinghouse H871N6

9/21/2013 11:55:32 AMRichard Dale Brown

Re: the Schematic for Westinghouse H871N6 Without the alignment procedure sheet I got the AM section aligned ok but I have no marker sig. gen and having trouble aligning the FM ratio det section. If I had the FM alignment instructions it would help. RDB

9/21/2013 12:26:25 PMCV

You could try the "agricultural method": assuming that you get at least some audio output, tune to a weak FM classical music station and merely adjust the ratio detector transformer slug until you get the best tone. Mis-adjustment of the ratio detector will result in distortion which is easy to detect with the ear. There will be a "sweet zone" for the detector; once you figure out where it is, and how wide it is, just run the slug to one end of the zone (where distortion just starts) then reverse enough to land in the middle of the adjustment range.

9/21/2013 4:49:02 PMRichard Dale Brown

:You could try the "agricultural method": assuming that you get at least some audio output, tune to a weak FM classical music station and merely adjust the ratio detector transformer slug until you get the best tone. Mis-adjustment of the ratio detector will result in distortion which is easy to detect with the ear. There will be a "sweet zone" for the detector; once you figure out where it is, and how wide it is, just run the slug to one end of the zone (where distortion just starts) then reverse enough to land in the middle of the adjustment range.
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9/21/2013 4:53:54 PMRichard Dale Brown

::You could try the "agricultural method": assuming that you get at least some audio output, tune to a weak FM classical music station and merely adjust the ratio detector transformer slug until you get the best tone. Mis-adjustment of the ratio detector will result in distortion which is easy to detect with the ear. There will be a "sweet zone" for the detector; once you figure out where it is, and how wide it is, just run the slug to one end of the zone (where distortion just starts) then reverse enough to land in the middle of the adjustment range.

Thanks for the info, I actually did that procedure and adjusted booth upper and lower slugs and got a fairly good non distorted sig.and audio out. Thanks again. RDB::
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