Panasonic 27XF25CW 27" TV Horizontal Line until warms up

B

bluespark

Guest
Hi, I'm a new user to this group. I have the above TV - GAOO, circa
2006,with the following symptoms.
When the TV is turned on and cold, there is bright horizontal line in
the middle of the screen with a flickering picture in the top half of
screen and bottom 1/2 is black. As the tv warms up, the image does
eventually fill in and the whole screen is more or less viewable. The
mid-section does continue to have some flickering lines, however, is
still reasonably viewable.
Can anyone direct me to whether this is a low voltage or HV issue?
Is this reasonably repairable or is it IC's etc all surface mount.
Appreciate any help.
 
On Sat, 13 Mar 2010 17:29:09 -0800 (PST), bluespark
<barry.hathaway@gmail.com> wrote:

Hi, I'm a new user to this group. I have the above TV - GAOO, circa
2006,with the following symptoms.
When the TV is turned on and cold, there is bright horizontal line in
the middle of the screen with a flickering picture in the top half of
screen and bottom 1/2 is black. As the tv warms up, the image does
eventually fill in and the whole screen is more or less viewable. The
mid-section does continue to have some flickering lines, however, is
still reasonably viewable.
Can anyone direct me to whether this is a low voltage or HV issue?
Is this reasonably repairable or is it IC's etc all surface mount.
Appreciate any help.
The symptoms would indicate a bad solder joint in the vertical
Click to expand...
deflection circuit (probably on the vertical deflection IC) or a bad
capacitor in the vertical deflection area.

This is definitely repairable by a competent technician, but do you
know enough about TVs to locate the suspect components and to work
safely?

PlainBill
 
On Sat, 13 Mar 2010 17:29:09 -0800 (PST), bluespark
<barry.hathaway@gmail.com> put finger to keyboard and composed:

Hi, I'm a new user to this group. I have the above TV - GAOO, circa
2006,with the following symptoms.
When the TV is turned on and cold, there is bright horizontal line in
the middle of the screen with a flickering picture in the top half of
screen and bottom 1/2 is black. As the tv warms up, the image does
eventually fill in and the whole screen is more or less viewable. The
mid-section does continue to have some flickering lines, however, is
still reasonably viewable.
Can anyone direct me to whether this is a low voltage or HV issue?
Is this reasonably repairable or is it IC's etc all surface mount.
Appreciate any help.
Click to expand...
The symptoms suggest a bad electrolytic capacitor near the vertical
amp IC. This is a low voltage issue. I'm not familiar with your model,
but the vertical IC will probably be attached to a heatsink, and will
probably have a part number beginning with AN, and be in a 9-pin (?)
SIP package.

Follow the 4-wire lead back from the deflection coils on the picture
tube. Two of the wires will go to the horizontal section (high
voltage), and the other two will go to the vertical amp (~25V).

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
 
Franc Zabkar <fzabkar@iinternode.on.net> writes:

On Sat, 13 Mar 2010 17:29:09 -0800 (PST), bluespark
barry.hathaway@gmail.com> put finger to keyboard and composed:

Hi, I'm a new user to this group. I have the above TV - GAOO, circa
2006,with the following symptoms.
When the TV is turned on and cold, there is bright horizontal line in
the middle of the screen with a flickering picture in the top half of
screen and bottom 1/2 is black. As the tv warms up, the image does
eventually fill in and the whole screen is more or less viewable. The
mid-section does continue to have some flickering lines, however, is
still reasonably viewable.
Can anyone direct me to whether this is a low voltage or HV issue?
Is this reasonably repairable or is it IC's etc all surface mount.
Appreciate any help.

The symptoms suggest a bad electrolytic capacitor near the vertical
amp IC. This is a low voltage issue. I'm not familiar with your model,
but the vertical IC will probably be attached to a heatsink, and will
probably have a part number beginning with AN, and be in a 9-pin (?)
SIP package.

Follow the 4-wire lead back from the deflection coils on the picture
tube. Two of the wires will go to the horizontal section (high
voltage), and the other two will go to the vertical amp (~25V).
Click to expand...
It is a low voltage issue, but there are HIGH VOLTAGES in the vicinity.

The OP needs to either have had experience in this type of electronics (which
it sounds like he does not) or at the very least, know enough to know what
not to touch! Read, understand, and follow the SAFETY GUIDELINES in the
TV Repair FAQ.

If in any doubt, get it repaired by a professional. This is not a major
repair.

--
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.



- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
Click to expand...
 
On Mar 14, 7:19 pm, s...@repairfaq.org (Samuel M. Goldwasser) wrote:
Franc Zabkar <fzab...@iinternode.on.net> writes:
On Sat, 13 Mar 2010 17:29:09 -0800 (PST), bluespark
barry.hatha...@gmail.com> put finger to keyboard and composed:

Hi, I'm a new user to this group.  I have the above TV - GAOO, circa
2006,with the following symptoms.
When the TV is turned on and cold, there is bright horizontal line in
the middle of the screen with a flickering picture in the top half of
screen and bottom 1/2 is black.  As the tv warms up, the image does
eventually fill in and the whole screen is more or less viewable.  The
mid-section does continue to have some flickering lines, however, is
still reasonably viewable.
Can anyone direct me to whether this is a low voltage or HV issue?
Is this reasonably repairable or is it IC's etc all surface mount.
Appreciate any help.

The symptoms suggest a bad electrolytic capacitor near the vertical
amp IC. This is a low voltage issue. I'm not familiar with your model,
but the vertical IC will probably be attached to a heatsink, and will
probably have a part number beginning with AN, and be in a 9-pin (?)
SIP package.

Follow the 4-wire lead back from the deflection coils on the picture
tube. Two of the wires will go to the horizontal section (high
voltage), and the other two will go to the vertical amp (~25V).

It is a low voltage issue, but there are HIGH VOLTAGES in the vicinity.

The OP needs to either have had experience in this type of electronics (which
it sounds like he does not) or at the very least, know enough to know what
not to touch!  Read, understand, and follow the SAFETY GUIDELINES in the
TV Repair FAQ.

If in any doubt, get it repaired by a professional.  This is not a major
repair.

--
    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..



- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
Click to expand...
Are there schematics avaiable online anywhere, free or purchase?
Thanks for helo ALL
 
On Fri, 2 Apr 2010 05:23:08 -0700 (PDT), bluespark
<barry.hathaway@gmail.com> put finger to keyboard and composed:

Are there schematics avaiable online anywhere, free or purchase?
Thanks for helo ALL
Click to expand...
Google turns up two suppliers for a service manual for a Panasonic
CT27XF25CW.

FWIW, here is a parts list:
http://crutchfield.partsearch.com/Model/Matsushita/Panasonic/CT27XF25CW.aspx?p=2&z=50&c=345ca7413bbd6939a98af01dd4a99a40&bs=Category&bd=Asc&ms=Category&md=Asc&k=#1

Your vertical output IC appears to be a Sanyo LA7845N:
http://www.audiolabga.com/pdf/LA7845N.pdf

There is an application diagram in the above datasheet.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
 
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