A couple of possibilities:
1) Mis-diagnosed shadow mask damage, problem in degaussing circuit or with
environmental magnetic field.
2) Problem started as a degaussing problem and you damaged the shadow mask
when bringing it to the shop.
It is unlikely that a shadow mask was damaged unless the set was moved or
dropped. From the description, I would guess a bad diagnosis. Typically,
shadow mask damage is not uniform nor circular. Usually one support will
detach and you get a weird ripple in the colors from a point on the side or
corner of the CRT. What you describe is much more like a degaussing circuit
that is malfunctioning. I'd have it diagnosed by another Sharp ASC.
Leonard
"CW" wrote in message
...
I have recently purchased a Sharp SX76NF100 76 cm pure flat screen TV.
This
TV has been refurbished by Sharp but it came with 12 months warranty. The
visible damages are on the cabinet (outer casing of the TV). These are
long
scatches but they do not extend onto the screen itself.
After 6 weeks of flawless operation, all of a sudden, on one morning,
after
turning on TV, I noticed severe colour distortion. I originally thought it
must have problems with antennas. I switched on DVD player and put the TV
on
AV. The same problem remained. Then I switched off the DVD player
completely
and the screen is supposed to go black. However, I noticed big red dot in
the middle of the screen, with blue colour circling the red dot, which is
in
turn encircled by yellow circle.
I immediately took the TV to a Sharp Repair centre and after much haggling
with Sharp, I was advised that the symptom is a manifestation of damaged
shadow mask, and it is not covered by manufacturer's warranty.
Specficially,
I was advised that damage to shadow mask could only come about with a
strong
impact. Since I advised Sharp that when I originally bought the TV, it was
in working order. Sharp surmised that I must have somehow dropped the TV
which caused the impact, and as such rejected the warranty request.
Now my problem is that I had never so much as moved the TV (which is about
50 KGs). It had been sitting on the TV stand since I bought it. I am
wondering if anyone here knows if there are any other reasons that shadow
mask could be damaged or any other problems that could cause the colour
distortions I mentioned earlier.
Thanks in advance
CW
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