On 27-Dec-2004, Tony wrote:

Hi, I have a Sharp 25K-S100 and the color convergence at the corners
is not good at all. The upper-left corner is especially bad and after
leaving the TV on for more than about 10 minutes, a small purple color
patch develops in that area. Any idea how I can repair this? I know
in the FAQ it mentions adjusting the ring magnets and the yolk, but
I'm not 100% sure how I would begin doing this, if this will even
work, and can I perform this with the television on to see if
everything will work ok? Please help me, thanks.

It halps if you have a manual or specific information on
converging Sharp sets. You have to converge with the set on
else you can't see what's happening. Most ring magnets are
stuck together with paint and it's a pain in the butt to separate
them without breaking them. It's quite easy to electrocute yourself
whilst watching the picture in a mirror, and not watching where
your hands are going. I use teletext to see convergence as it's
impossible to converge on a normal picture. Mark the position
of the rings before you start so you can get back to where they were.
Make sure the degauss circuit is working before you start, it
may be the only thing that is wrong. It may not be possible to
converge the set if it has had the flyback replaced with a
generic. Some sets need stick on magnets to sort out
problems at the screen corners. Removing metal screens,
if there are any, can upset convergence, so the history of
repairs may provide a clue as to why the convergence is off.
To do the job properly you need a convergence pattern
generator, a DVD player on pause, with text such as
the distribution rights on the screen, or teletext is a poor
substitute. If a generic flyback has been used the EHT may
be out of spec, and if the scan amplitudes have been adjusted
to compensate for the different sensitivity due to the
changed EHT, you've got problems, which is why the sets
history is useful, like when did the problem appear, just after
a repair?