A KP48V75 should not be a point in its service life where the CRTs are no
focusing well unless it has been run much more than a typical consumer
would. It probably came from the factory looking like this. I don't recall
if Sony intentionally defocused the blue on this one or not and the Sony ESI
site is not coming up at all and my discs are at the shop. Has anyone else
been having trouble getting to the site for the last few days?

Blue phosphors do not focus as tightly as red and green, true enough. It is
not, however, necessary to defocus the blue to get good white balance or
gray scale tracking. The reason that many manufacturers defocused the blue
was to get more output, this is correct. This accomplished two things, a
brighter picture at white peak (desirable in showroom comparisons) at a
higher color temperature (more blue whites a.k.a. a "trinitron" look with
pinker flesh tones). Running the contrast a little lower, focusing the blue
correctly (for best focus), and readjusting the white balance for your
preferred color temperature almost always gives a better result and also
gives longer tube life with less burn-in problems. RPTV brightness levels
have bee higher than needed for good viewing in a normal home environment
for years. "Torching" the CRTs the way the manufacturers set them up is
simply not necessary.

Even if the service manual says to defocus the blue that does not mean that
it is the best solution. The approximately 9500 degree color temperature
that the manufacturers are (were) able to get by doing so is considered by
most people who understand color reproduction, and many casual viewers, to
be "wrong". Actually the practice of defocusing the blue has been going
away as we move to HD because there is agreement that a lower color
temperature is more correct and the defocusing procedure limits resolution.
Nobody wants a "soft" HD image and most HD buyers are more attentive to
issues such as color temperature, focus, and convergence.

A good reference document with more than most of us want to know about color
is provided by Charles Poynton at
http://www.poynton.com/PDFs/ColorFAQ.pdf

Leonard Caillouet

"David" wrote in message
...
How much 'blue halo"?
Sony low end RPTV sets, especially those with the narrow cabinet have an
average optical focus on the red and blue due to not using the more
expensive lenses that compensate for the difference in distance between
the
left and right tubes.
In addition due to the lower output of the phosphor, the blue is out of
focus by design to allow proper gray scale tracking. A certain amount of
defocus is expected and normal. This is why the amount of halo is very
important and critical to determine if there really is an adjustment
needed.

It could simply be the blue tube is getting soft with age and is outside
of
proper focus range.

Most Sony RPTV sets use a focus block on the hv divider for electrical
focus, there is also an optical focus. It is strongly suggested you
consult
the service adjustment manual to verify the proper focus procedure and
amount for the blue tube. You will likely find that a gray scale
adjustment
will be required after adjusting the blue focus on that set.

David

jim's wrote in message
...
Wondering how to make this adjustment. The service manual states to
adjust the FOCUS knob? I can not find it, can someone point me in the
right direction on this one?
The reason, I think, this need to be adjusted is that the "blue lines"
have a halo of blue around them.
Thanks for the help.
Jim