NEC N-1426A TV Keystone Picture

J

Jared

Guest
Problem with NEC N-1426A TV, the raster is now keystone shaped (see
following ascii diagram). I'm hoping its not a problem with the
deflection coils, and would welcome any other suggestions or maybe a
schematic.


TV PICTURE SHAPE:
-----------
\ /
\ /
\-----/


TIA,
Jared
 
Usually this is definitely the deflection coils. In some assemblies, there
are some small caps located in the deflection coil assembly. I have seen
these go shorted, thus causing some defects in the scanning, but this is
rare. It is also possible, from what I have heard, to have a short between
the scans on the main board, but with all the sets I have serviced, I have
not personally run in to this before.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Jared" <jaz_shnat@hotmail.com> wrote in message
news:98bc4967.0401110507.25ff8790@posting.google.com...
Problem with NEC N-1426A TV, the raster is now keystone shaped (see
following ascii diagram). I'm hoping its not a problem with the
deflection coils, and would welcome any other suggestions or maybe a
schematic.


TV PICTURE SHAPE:
-----------
\ /
\ /
\-----/


TIA,
Jared
 
Well I followed the procedure in the repair FAQ of swapping the
working deflection axis and seeing if the shape of the picture
changed. It did not, which indicates that the problem lies with the
deflection coils, however I have since removed the yoke and under
inspection was unable to spot any obvious black or charred sections.
Does this mean I have made an incorrect diagnosis? Or is it possible
to have a fauly coil w/o any visible signs??

"Jerry G." <jerryg50@hotmail.com> wrote in message news:<btrkoh$ef3$7@news.eusc.inter.net>...
Usually this is definitely the deflection coils. In some assemblies, there
are some small caps located in the deflection coil assembly. I have seen
these go shorted, thus causing some defects in the scanning, but this is
rare. It is also possible, from what I have heard, to have a short between
the scans on the main board, but with all the sets I have serviced, I have
not personally run in to this before.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Jared" <jaz_shnat@hotmail.com> wrote in message
news:98bc4967.0401110507.25ff8790@posting.google.com...
Problem with NEC N-1426A TV, the raster is now keystone shaped (see
following ascii diagram). I'm hoping its not a problem with the
deflection coils, and would welcome any other suggestions or maybe a
schematic.


TV PICTURE SHAPE:
-----------
\ /
\ /
\-----/


TIA,
Jared
Click to expand...
 
Jared wrote:
Well I followed the procedure in the repair FAQ of swapping the
working deflection axis and seeing if the shape of the picture
changed. It did not, which indicates that the problem lies with the
deflection coils, however I have since removed the yoke and under
inspection was unable to spot any obvious black or charred sections.
Does this mean I have made an incorrect diagnosis? Or is it possible
to have a fauly coil w/o any visible signs??
Click to expand...
From the model number I would assume it's a 14" set? Other than very
large screen cets such as 27"+ CRTs and projections TVs don't have a
pincushion circuit that could cause a keystone image. It has to be a
short in the deflection yoke. They're usually not visible.
--
Andy Cuffe
baltimora@psu.edu
 
On 11 Jan 2004 05:07:28 -0800, jaz_shnat@hotmail.com (Jared) put
finger to keyboard and composed:

Problem with NEC N-1426A TV, the raster is now keystone shaped (see
following ascii diagram). I'm hoping its not a problem with the
deflection coils, and would welcome any other suggestions or maybe a
schematic.


TV PICTURE SHAPE:
-----------
\ /
\ /
\-----/


TIA,
Jared
Click to expand...
Just a guess, but does the yoke have one of these part numbers:

DIE1492HL, TCY120PPF, ODYM1401, DSE1422FL


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