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

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

"Leonard Caillouet" writes:

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.

Agreed. They (the Sharp rep or whoever) may have just concluded that there
was damage since the case had those scratches. It would be a simple matter
to manually degauss it with power on to determine if the shadow mask is
undamaged.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the feedback form on the S.E.R FAQ Web sites.




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

Guys, thanks for the help.

"Sam Goldwasser" wrote in message
...
"Leonard Caillouet" writes:

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.

Agreed. They (the Sharp rep or whoever) may have just concluded that
there
was damage since the case had those scratches. It would be a simple
matter
to manually degauss it with power on to determine if the shadow mask is
undamaged.

--- sam | Sci.Electronics.Repair FAQ Mirror:
http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ:
http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites:
http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the
excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header is
ignored.
To contact me, please use the feedback form on the S.E.R FAQ Web sites.




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

To my perception and experience, your suggestions are very accurate! I would
take the set back, and ask them to use a manual degaussing coil on the set.
If this works, tell them to fix the degaussing circuit. If not, then they
are right that the shadowmask is broken.

When buying a used set, you have no idea of how it was handled before, even
though the picture at the time looked okay to you. I have seen the
shadowmask go bad in tubes where the set was not abused. All it takes is one
of the support wires to go bad. These wires are under tension, and can break
on their own, even though it is rare. I may have seen this only a small
number of times, but I have seen a lot of sets.

Personally, from what I have seen, I would never buy a re-furbished
appliance or device of any type that has value. Since I used to be working
in that part of the business, I can bring up many reasons, and tell many
aspects of what happens with most of the refurbishing contracts. This can be
a long topic in itself. Very few of the refurbishes are properly servicing
the sets, and having them resent out again in proper working order.

--

Jerry G.
==========================


"Leonard Caillouet" wrote in message
news:NCkWc.8029$L94.4491@fed1read07...
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

Is manual degaussing an option available to end user or must service centre
do the job?

"Sam Goldwasser" wrote in message
...
"Leonard Caillouet" writes:

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.

Agreed. They (the Sharp rep or whoever) may have just concluded that
there
was damage since the case had those scratches. It would be a simple
matter
to manually degauss it with power on to determine if the shadow mask is
undamaged.

--- sam | Sci.Electronics.Repair FAQ Mirror:
http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ:
http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites:
http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the
excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header is
ignored.
To contact me, please use the feedback form on the S.E.R FAQ Web sites.




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

"CW" writes:

Is manual degaussing an option available to end user or must service centre
do the job?

There are many ways to do it but if the internal degauss circuit is
faulty, it's not a long term solution.

See:

http://repairfaq.ece.drexel.edu/sam/crtfaq.htm#crtmdg

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the feedback form on the S.E.R FAQ Web sites.

Hi!

I bought a Magnavox 19" table top TV set in very similar condition to your
set...it has a large "crink" in the casing at the upper left of the tube.
The case isn't shattered or even broken, it's just compressed. I guess the
thing took quite a fall and when I was considering buying it, the picture
was all purple. The price was right, and the reseller offered a four year
guarantee that made the total just shy of what a new in the box set would
have cost. I bought the set and still use it daily.

Going over the screen with a tape head demagnetizer (all I had at the time)
brought back perfect color. It appears that the set's built in degaussing
coil is not working. Every now and then the picture will start to discolor,
especially after I've moved my TV cart around. I just take a few minutes to
degauss it once again and all is well.

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 wouldn't think that the tube could suddenly be damaged like that,
especially if it hasn't seen any more abuse since you bought it. You might
have a chance that like mine, your TV's built in degaussing coil has failed
to work.

You might try getting ahold of a degaussing tool somewhere and trying it.
You might get lucky and the set will be fine.

William