Sony KV-32FS13 bright with retrace lines

A

Andy Cuffe

Guest
I'm working on a KV-32FS13 for a friend, but due to its location I
can't get much time with it, so I'm looking for any model specific
tips so I don't have to make too many trips.

The symptoms are that it turns on, but you get a bright white raster
with retrace lines and then it shuts down. I was able to prevent
shutdown by turning the screen control to minimum, but there is still
a bright raster with retrace lines. You can still see the picture
behind the retrace lines. All 3 cathodes are at about 3v which is
obviously way too low. Does this set have a history of video output
IC, or other failures that cause this problem? It would be nice if I
knew what to take next time I look at the set.
Andy Cuffe
baltimora@psu.edu
 
I am betting on the CRT being finished. These CRT's can go internally
shorted out, and do this.

--

Greetings,

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


"Andy Cuffe" <baltimora@psu.edu> wrote in message
news:66ak50haotm2eifa4l1ns0a9dvpjkht3v3@4ax.com...
I'm working on a KV-32FS13 for a friend, but due to its location I
can't get much time with it, so I'm looking for any model specific
tips so I don't have to make too many trips.

The symptoms are that it turns on, but you get a bright white raster
with retrace lines and then it shuts down. I was able to prevent
shutdown by turning the screen control to minimum, but there is still
a bright raster with retrace lines. You can still see the picture
behind the retrace lines. All 3 cathodes are at about 3v which is
obviously way too low. Does this set have a history of video output
IC, or other failures that cause this problem? It would be nice if I
knew what to take next time I look at the set.
Andy Cuffe
baltimora@psu.edu
 
I am betting on the CRT being finished. These CRT's can go internally
shorted out, and do this.
Click to expand...
You can tell by unplugging the CRT board from the tube and measure your
cathodes. If voltage is back to normal 150-200v, tube is shorted. Of course
when a tube shorts it is normally only one gun, so my thoughts is you've lost
the 200v supply to the video outputs.
Ron
 
On 19 Mar 2004 01:53:18 GMT, ronkz650@aol.comnospam (RonKZ650) wrote:

I am betting on the CRT being finished. These CRT's can go internally
shorted out, and do this.

You can tell by unplugging the CRT board from the tube and measure your
cathodes. If voltage is back to normal 150-200v, tube is shorted. Of course
when a tube shorts it is normally only one gun, so my thoughts is you've lost
the 200v supply to the video outputs.
Ron
Click to expand...

The 200v supply is there. I can't see what type of CRT failure could
cause this since all 3 guns are affected equally. With the CRT socket
removed, the cathode voltages all go to 0v, but that's probably
because of the AKB circuit.
Andy Cuffe
baltimora@psu.edu
 
Try changing the TDA6108 IC on the CRT board.


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================
"If you push something hard enough it will fall over."
Fudd's First Law of Opposition - Sir Sidney Fudd


"Andy Cuffe" <baltimora@psu.edu> wrote in message
news:66ak50haotm2eifa4l1ns0a9dvpjkht3v3@4ax.com...
I'm working on a KV-32FS13 for a friend, but due to its location I
can't get much time with it, so I'm looking for any model specific
tips so I don't have to make too many trips.

The symptoms are that it turns on, but you get a bright white raster
with retrace lines and then it shuts down. I was able to prevent
shutdown by turning the screen control to minimum, but there is still
a bright raster with retrace lines. You can still see the picture
behind the retrace lines. All 3 cathodes are at about 3v which is
obviously way too low. Does this set have a history of video output
IC, or other failures that cause this problem? It would be nice if I
knew what to take next time I look at the set.
Andy Cuffe
baltimora@psu.edu
Click to expand...
 
"Shoreline Electronics" <jstielau@snet.net> wrote in message news:<oKt6c.37152$6H3.18564@newssvr16.news.prodigy.com>...
Try changing the TDA6108 IC on the CRT board.


--
==========================
Jeff Stielau
Click to expand...

I swapped the TDA6108 with one from a junk set. Now I have a black
screen and flashing power light. The AKB pulses are visible on the
cathodes (they weren't before), but I've only been able to get the
picture to unblank a few times and only for a few seconds. When it
did unblank, it was over bright, but otherwise normal. I've traced
the AKB pulses back to the CXA2154. Can anyone give me some details
on the correct amplitude of the AKB pulses? Right now there's about
200v on the cathodes with the AKB pulses clearly visible. The size of
the pulses decreases when I turn up the G2, but it won't unblank, even
if I turn the G2 up enough to see retrace lines.

Andy
 
After some more work, it looks like my TDA6108 from the junk board was
also bad. I found that the AKB unblanked when I had scope probes on
any two of the cathodes, but that there was virtually no blue.
Swapping the blue and green inputs to the video output IC anc swapping
the outputs to the CRT resulted in weak green instead of blue. I also
noticed that the AKB pulses on that channel aren't behaving correctly
when the G2 is adjusted. It's hard to believe someone junked this set
for such a minor problem (it was a curb pickup). I don't think the
back had ever been off the set.

Andy Cuffe
baltimora@psu.edu
 
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