[EXPERT TIPS][MR BOB]
Danger -- C Lin, S Lin, etc. (Convergence)
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Attention all DIY-ers! Convergence warning to those who don’t have the simpler
convergence patterns like the 64 point and the usual Mitsubishi quadrant array, and the
Zenith/Ampro projector types. These are EASY compared to the older Sony and Pioneer types,
which contain hidden land mines. This also includes the TS series of Mits’s, which is
mostly quadrant type, but has a few “added features” in its convergence
array.
Some of the worst U.S. Marine language ever heard, I’m certain, has come from the
mouths of innocent-minded big screen DIY-ers, who stepped on the land mines called S Lin,
C Lin, Mid Lin, Mid Pin, etc. -- all versions of Linearity and Pincushion.
These innocent-sounding labels gloss over the fact that each of these locations in your
convergence circuit completely rebias the entire linearity and pincusion curves used in
these particular algorithms in the convergence pattern generator of your big screen.
ALL SUCH LOCATIONS ABSOLUTELY NEED TO BE RECORDED BEFORE ALTERED.
This means using a THIN Sharpie pen mark on screwdriver pots, and/or writing down the
values you started with, if done in a remote-controlled service menu. You HAVE to know
where you started, on each pass, to be able to get these right.
I strongly suggest NOT TOUCHING THEM! EVER! Leave this
part of your calibration to a professional—and this eliminates 90% of the warranty
and freelance service techs out there, who are repairpeople, and abysmally ignorant of
such finer points as this.
This means, if you have a service tech over to do your convergence, it would be a VERY
good idea to make sure he doesn’t touch any of these controls. Get him to agree to
it, unless he can make you feel comfortable that he knows what he’s doing around
these particular parameters/controls.
Even I, as a professional tweaker, cringe whenever I have to remedy a problem involving
these parameters; and be forewarned, to do so is NOT covered in the basic calibration
package I offer. If you or anybody else has already futzed with them at all -- or even if
you simply are not satisfied with the factory settings -- and I am asked to redo them to
make your picture better, be prepared to pay extra. Otherwise we leave them as they are
and work the rest of the convergence around them.
Sub Pin and Sub Key are much more predictable, tho they also require special attention,
such as redoing the width/height and regular linearity to compensate, on each pass with
these parameters. The others are in a league of their own.
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