Hi all,

Having a Panasonic television CT-27... with a color problem. There is a kind
of big circle on the screen and the color is not right around thiscircle.
King of purple and yellow.

It looks like a perfect circle so I'm assuming something in the tube itself
is bad. Shadow mask ? Problem with the Degauss ?

Any idea ?

Tks for you help...

On Apr 3, 11:34 am, "Max" wrote:
Hi all,

Having a Panasonic television CT-27... with a color problem. There is a kind
of big circle on the screen and the color is not right around thiscircle.
King of purple and yellow.

It looks like a perfect circle so I'm assuming something in the tube itself
is bad. Shadow mask ? Problem with the Degauss ?

Any idea ?

Tks for you help...

someone probably put a speaker or other magnet against it or it is
impact damage.try replacing the degauss posistor first.
-B

In article .com,
b wrote:
On Apr 3, 11:34 am, "Max" wrote:
Hi all,

Having a Panasonic television CT-27... with a color problem. There is
a kind of big circle on the screen and the color is not right around
thiscircle. King of purple and yellow.

It looks like a perfect circle so I'm assuming something in the tube
itself is bad. Shadow mask ? Problem with the Degauss ?

Any idea ?

Tks for you help...

someone probably put a speaker or other magnet against it or it is
impact damage.try replacing the degauss posistor first.

The built in degauss won't fix a bad case. Needs external degaussing. A
repair shop should be able to do this.

--
*Why do overlook and oversee mean opposite things? *

Dave Plowman London SW
To e-mail, change noise into sound.

"Max" writes:

Hi all,

Having a Panasonic television CT-27... with a color problem. There is a kind
of big circle on the screen and the color is not right around thiscircle.
King of purple and yellow.

It looks like a perfect circle so I'm assuming something in the tube itself
is bad. Shadow mask ? Problem with the Degauss ?

Was it dropped?

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

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

The unit dhas not been dropped and no speaker has been put near the TV.

Unit was OK and went bad just like that.

You can easily see a big circle in the middle...

"Sam Goldwasser" wrote in message
...
"Max" writes:

Hi all,

Having a Panasonic television CT-27... with a color problem. There is a
kind
of big circle on the screen and the color is not right around thiscircle.
King of purple and yellow.

It looks like a perfect circle so I'm assuming something in the tube
itself
is bad. Shadow mask ? Problem with the Degauss ?

Was it dropped?

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

Important: Anything sent to the email address in the message header above
is
ignored unless my full name AND either lasers or electronics is included
in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

On Tue, 3 Apr 2007 10:38:02 -0400, "Max" wrote:

The unit dhas not been dropped and no speaker has been put near the TV.

Unit was OK and went bad just like that.

You can easily see a big circle in the middle...


In that case I would say that either the degaussing circuit has
failed, or the deflection yoke is loose and has slipped back on the
neck of the CRT. Both of these problems are minor and will cause the
problem you describe. Manual degaussing won't fix either of these
problems.
Andy Cuffe

On 3 Apr, 20:40, Andy Cuffe wrote:
On Tue, 3 Apr 2007 10:38:02 -0400, "Max" wrote:

The unit dhas not been dropped and no speaker has been put near the TV.

Unit was OK and went bad just like that.

You can easily see a big circle in the middle...

In that case I would say that either the degaussing circuit has
failed, or the deflection yoke is loose and has slipped back on the
neck of the CRT. Both of these problems are minor and will cause the
problem you describe. Manual degaussing won't fix either of these
problems.
Andy Cuffe



in some cases moving of scan coils back can result in tube explosion.


NT

On Apr 3, 8:12 pm, wrote:
On 3 Apr, 20:40, Andy Cuffe wrote:

On Tue, 3 Apr 2007 10:38:02 -0400, "Max" wrote:
The unit dhas not been dropped and no speaker has been put near the TV.

Unit was OK and went bad just like that.

You can easily see a big circle in the middle...

In that case I would say that either the degaussing circuit has
failed, or the deflection yoke is loose and has slipped back on the
neck of the CRT. Both of these problems are minor and will cause the
problem you describe. Manual degaussing won't fix either of these
problems.
Andy Cuffe



in some cases moving of scan coils back can result in tube explosion.

NT


In some cases dropping a CRT onto concrete can result in breakage,
Huh??

Bruce

Circular magnetic effects are usually due to the degaussing circuit
malfunctioning or a power surge such as happens with a nearby lightning
strike. The former is very common on Panasonic sets, could be bad solder
connections at the degaussing thermistor or a bad thermistor.

If it is the latter problem, manual degaussing may be needed.

Leonard

"Max" wrote in message
...
Hi all,

Having a Panasonic television CT-27... with a color problem. There is a
kind of big circle on the screen and the color is not right around
thiscircle. King of purple and yellow.

It looks like a perfect circle so I'm assuming something in the tube
itself is bad. Shadow mask ? Problem with the Degauss ?

Any idea ?

Tks for you help...

Hi All ,

The thermistor has been tested OK and solder joints are OK.

How to confirm that it's not the tube ? Shadow mask ?

Should I try to degauss it anyway ?

Tks for you help...

"Leonard Caillouet" wrote in message
...
Circular magnetic effects are usually due to the degaussing circuit
malfunctioning or a power surge such as happens with a nearby lightning
strike. The former is very common on Panasonic sets, could be bad solder
connections at the degaussing thermistor or a bad thermistor.

If it is the latter problem, manual degaussing may be needed.

Leonard

"Max" wrote in message
...
Hi all,

Having a Panasonic television CT-27... with a color problem. There is a
kind of big circle on the screen and the color is not right around
thiscircle. King of purple and yellow.

It looks like a perfect circle so I'm assuming something in the tube
itself is bad. Shadow mask ? Problem with the Degauss ?

Any idea ?

Tks for you help...

You may have had a nearby lightning strike? We see sets all the time that
have been subjected to a surge that have the tube magnetized by the
degausing coil to the extent that the internal degaussing cannot demagnetize
the tube.

The fact that it is circular indicates that the source of the magnetic field
is likely the degaussing coil itself. A damaged CRT shadow mask will almost
always give you adifferential symptom at the edges on one side.

Leonard

"Max" wrote in message
...
Hi All ,

The thermistor has been tested OK and solder joints are OK.

How to confirm that it's not the tube ? Shadow mask ?

Should I try to degauss it anyway ?

Tks for you help...

"Leonard Caillouet" wrote in message
...
Circular magnetic effects are usually due to the degaussing circuit
malfunctioning or a power surge such as happens with a nearby lightning
strike. The former is very common on Panasonic sets, could be bad solder
connections at the degaussing thermistor or a bad thermistor.

If it is the latter problem, manual degaussing may be needed.

Leonard

"Max" wrote in message
...
Hi all,

Having a Panasonic television CT-27... with a color problem. There is a
kind of big circle on the screen and the color is not right around
thiscircle. King of purple and yellow.

It looks like a perfect circle so I'm assuming something in the tube
itself is bad. Shadow mask ? Problem with the Degauss ?

Any idea ?

Tks for you help...

Right on !

I use an external degauss coil and it's OK now.

Tks.


"Leonard Caillouet" wrote in message
...
You may have had a nearby lightning strike? We see sets all the time that
have been subjected to a surge that have the tube magnetized by the
degausing coil to the extent that the internal degaussing cannot
demagnetize the tube.

The fact that it is circular indicates that the source of the magnetic
field is likely the degaussing coil itself. A damaged CRT shadow mask
will almost always give you adifferential symptom at the edges on one
side.

Leonard

"Max" wrote in message
...
Hi All ,

The thermistor has been tested OK and solder joints are OK.

How to confirm that it's not the tube ? Shadow mask ?

Should I try to degauss it anyway ?

Tks for you help...

"Leonard Caillouet" wrote in message
...
Circular magnetic effects are usually due to the degaussing circuit
malfunctioning or a power surge such as happens with a nearby lightning
strike. The former is very common on Panasonic sets, could be bad
solder connections at the degaussing thermistor or a bad thermistor.

If it is the latter problem, manual degaussing may be needed.

Leonard

"Max" wrote in message
...
Hi all,

Having a Panasonic television CT-27... with a color problem. There is a
kind of big circle on the screen and the color is not right around
thiscircle. King of purple and yellow.

It looks like a perfect circle so I'm assuming something in the tube
itself is bad. Shadow mask ? Problem with the Degauss ?

Any idea ?

Tks for you help...