Another Problem TV Thrown My Way - Sony KV27S42 - Purity Problems
 

This one was dropped on the bottom left corner by the looks of the
cracks in the case. Now it has bad purity down the left side, and the
bottom right corner. I have found some info on the net here;

http://videotech.lesterville.com/sony.htm

I thought I would check here to see if there are any alternatives to
trying magnets etc to get the purity back. I seem to recall that the
rings on the neck of the CRT used to be used for purity too, but these
ones have not moved.

Thanks,

- Tim -

Another Problem TV Thrown My Way - Sony KV27S42 - Purity Problems
 

In article , l says...
On Fri, 11 May 2007 15:18:59 -0300, Tim wrote:

This one was dropped on the bottom left corner by the looks of the
cracks in the case. Now it has bad purity down the left side, and the
bottom right corner. I have found some info on the net here;

http://videotech.lesterville.com/sony.htm

I thought I would check here to see if there are any alternatives to
trying magnets etc to get the purity back. I seem to recall that the
rings on the neck of the CRT used to be used for purity too, but these
ones have not moved.

Thanks,


If it was dropped the shadow mask inside the tube has shifted and you need
magnets.


I thought it would be something like that. I experimented with my
magnetic screwdriver, and I was able to almost eliminate most of the
problem on the left side while it was near the back of the CRT, so maybe
I'll experiment some more with magnets.

It probably doesn't matter at this point, but I had the symptoms
reversed. It was dropped on the right corner and the purity problem was
mostly down the left side.

Thanks for the info.

- Tim -

Another Problem TV Thrown My Way - Sony KV27S42 - Purity Problems
 

On May 11, 5:00 pm, Tim wrote:
In article , says...



On Fri, 11 May 2007 15:18:59 -0300, Tim wrote:

This one was dropped on the bottom left corner by the looks of the
cracks in the case. Now it has bad purity down the left side, and the
bottom right corner. I have found some info on the net here;

http://videotech.lesterville.com/sony.htm

I thought I would check here to see if there are any alternatives to
trying magnets etc to get the purity back. I seem to recall that the
rings on the neck of the CRT used to be used for purity too, but these
ones have not moved.

Thanks,

If it was dropped the shadow mask inside the tube has shifted and you need
magnets.

I thought it would be something like that. I experimented with my
magnetic screwdriver, and I was able to almost eliminate most of the
problem on the left side while it was near the back of the CRT, so maybe
I'll experiment some more with magnets.

It probably doesn't matter at this point, but I had the symptoms
reversed. It was dropped on the right corner and the purity problem was
mostly down the left side.

Thanks for the info.

- Tim -- Hide quoted text -

- Show quoted text -

I used to cement small magnets to the picture tube glass bell using
silicon rubber.

H. R.(Bob) Hofmann

Hi Tim

I think you have a CRT trouble. Inner CRT hole mask may be out of position or deformed because dropped. Sometimes after a big hit, purity and/or rainbow patterns appear across the screen. There are no ways to fix this kind of patterns even with magnets or convergence yoke rings.

If you don't have such patterns, it may be a degaussing circuit fault. It often fails down about thermistor terminals soldering. You should check if this circuit works properly. Be careful because Thermistor is hot mostly. It is always close the relay and connects to degaussing coil behind the screen.

Hope this help.

Regards

John_H

Another Problem TV Thrown My Way - Sony KV27S42 - Purity Problems - Almost Fixed
 

In article ,
says...
In article , l says...
On Fri, 11 May 2007 15:18:59 -0300, Tim wrote:

This one was dropped on the bottom left corner by the looks of the
cracks in the case. Now it has bad purity down the left side, and the
bottom right corner. I have found some info on the net here;

http://videotech.lesterville.com/sony.htm

I thought I would check here to see if there are any alternatives to
trying magnets etc to get the purity back. I seem to recall that the
rings on the neck of the CRT used to be used for purity too, but these
ones have not moved.

Thanks,


If it was dropped the shadow mask inside the tube has shifted and you need
magnets.


I thought it would be something like that. I experimented with my
magnetic screwdriver, and I was able to almost eliminate most of the
problem on the left side while it was near the back of the CRT, so maybe
I'll experiment some more with magnets.

It probably doesn't matter at this point, but I had the symptoms
reversed. It was dropped on the right corner and the purity problem was
mostly down the left side.

Thanks for the info.

- Tim -

Just an update...

I have 6 magnets on the CRT right now, and the problem is almost gone. I
just have to remove one small area at the top and it will be good as new
again. It's hard to imagine that sticking magnets on the CRT would
resolve the issue so well, but hey the results prove the theory.

I'll get at it again tomorrow.

Thanks to Meat Plow for the heads up...

- Tim -

Another Problem TV Thrown My Way - Sony KV27S42 - Purity Problems
 

In article . com,
says...
On May 11, 5:00 pm, Tim wrote:
In article , says...



On Fri, 11 May 2007 15:18:59 -0300, Tim wrote:

This one was dropped on the bottom left corner by the looks of the
cracks in the case. Now it has bad purity down the left side, and the
bottom right corner. I have found some info on the net here;

http://videotech.lesterville.com/sony.htm

I thought I would check here to see if there are any alternatives to
trying magnets etc to get the purity back. I seem to recall that the
rings on the neck of the CRT used to be used for purity too, but these
ones have not moved.

Thanks,

If it was dropped the shadow mask inside the tube has shifted and you need
magnets.

I thought it would be something like that. I experimented with my
magnetic screwdriver, and I was able to almost eliminate most of the
problem on the left side while it was near the back of the CRT, so maybe
I'll experiment some more with magnets.

It probably doesn't matter at this point, but I had the symptoms
reversed. It was dropped on the right corner and the purity problem was
mostly down the left side.

Thanks for the info.

- Tim -- Hide quoted text -

- Show quoted text -

I used to cement small magnets to the picture tube glass bell using
silicon rubber.

H. R.(Bob) Hofmann


I used double sided foam tape after cleaning the glass. I saw that there
was a small circular one already attached that way, so I copied the
method. If they fall off, I'll use your silicon rubber idea.

Thanks,

- Tim -

Another Problem TV Thrown My Way - Sony KV27S42 - Purity Problems
 

In the Sony sets, the purity magnets should be very well glued in to place.
Going from experience, the shadowmask in the CRT is probably damaged. These
sets are so sensitive, that a small drop can damage the shadow mask.

--

JANA
_____


"Tim" wrote in message
...
This one was dropped on the bottom left corner by the looks of the
cracks in the case. Now it has bad purity down the left side, and the
bottom right corner. I have found some info on the net here;

http://videotech.lesterville.com/sony.htm

I thought I would check here to see if there are any alternatives to
trying magnets etc to get the purity back. I seem to recall that the
rings on the neck of the CRT used to be used for purity too, but these
ones have not moved.

Thanks,

- Tim -

Another Problem TV Thrown My Way - Sony KV27S42 - Purity Problems Fixed, But Need Menu Help
 

In article ,
says...
This one was dropped on the bottom left corner by the looks of the
cracks in the case. Now it has bad purity down the left side, and the
bottom right corner. I have found some info on the net here;

http://videotech.lesterville.com/sony.htm

I thought I would check here to see if there are any alternatives to
trying magnets etc to get the purity back. I seem to recall that the
rings on the neck of the CRT used to be used for purity too, but these
ones have not moved.

Thanks,

- Tim -

OK I have the purity fixed up perfectly now. I need to adjust the
rotation (tilt) of the pic tho, it is off by about 3/8". Does this set
have that adjustment in a service menu? I would need to know how to
activate that menu. I know I could open the set up again and adjust the
yoke manually, but I like to try the electronic tilt if possible.

Thanks,

- Tim -

Another Problem TV Thrown My Way - Sony KV27S42 - Purity Problems Fixed, But Need Menu Help
 

Did you try to degauss the tube (a power cycle) after placing the
magnets?
Most of the times it will cancel their effect. On a similar problem
the only fix I found was to unplug the degausser once the CRT was left
properly magnetized and installed at its definitive place. A big
speaker magnet works pretty well at magnetizing CRTs.

Tim wrote:
In article ,
says...
This one was dropped on the bottom left corner by the looks of the
cracks in the case. Now it has bad purity down the left side, and the
bottom right corner. I have found some info on the net here;

http://videotech.lesterville.com/sony.htm

I thought I would check here to see if there are any alternatives to
trying magnets etc to get the purity back. I seem to recall that the
rings on the neck of the CRT used to be used for purity too, but these
ones have not moved.

Thanks,

- Tim -

OK I have the purity fixed up perfectly now. I need to adjust the
rotation (tilt) of the pic tho, it is off by about 3/8". Does this set
have that adjustment in a service menu? I would need to know how to
activate that menu. I know I could open the set up again and adjust the
yoke manually, but I like to try the electronic tilt if possible.

Thanks,

- Tim -

Another Problem TV Thrown My Way - Sony KV27S42 - Purity Problems Fixed, But Need Menu Help
 

The set has been cycled many times since I placed the magnets on the
back bell of the tube. I did get some Silicon II to attach them with
tho, as I decided the double sided tape may let go after a bit. It still
looks great, just tilted now.

It was my understanding that trying to demagnetize the CRT is not
advisable because it will destroy the conditioning of the tube and it
will never return to proper purity again. And it really has come back
nicely, so I don't see the need to try and manually degauss the CRT.

In article . com,
says...
Did you try to degauss the tube (a power cycle) after placing the
magnets?
Most of the times it will cancel their effect. On a similar problem
the only fix I found was to unplug the degausser once the CRT was left
properly magnetized and installed at its definitive place. A big
speaker magnet works pretty well at magnetizing CRTs.

Tim wrote:
In article ,
says...
This one was dropped on the bottom left corner by the looks of the
cracks in the case. Now it has bad purity down the left side, and the
bottom right corner. I have found some info on the net here;

http://videotech.lesterville.com/sony.htm

I thought I would check here to see if there are any alternatives to
trying magnets etc to get the purity back. I seem to recall that the
rings on the neck of the CRT used to be used for purity too, but these
ones have not moved.

Thanks,

- Tim -

OK I have the purity fixed up perfectly now. I need to adjust the
rotation (tilt) of the pic tho, it is off by about 3/8". Does this set
have that adjustment in a service menu? I would need to know how to
activate that menu. I know I could open the set up again and adjust the
yoke manually, but I like to try the electronic tilt if possible.

Thanks,

- Tim -