TV problems - Mitsubishi CS-31301C

[neil.tuttle@gmail.com]

Hello!

We recently got a nice big TV for free (from the trash) and it has a
couple problems that I would like to fix!

Mitsubishi CS-31301C

The first problem is the most annoying...the screen rolls from bottom
to top. It will do this very fast, sometimes it's so fast it just kind
of flickers. It only occurs on some channels, or at least is only very
BAD on some channels, and is definitely worse when the TV hasn't been
used for a few hours (it's cold). It doesn't effect the OSD at all -
the OSD stays rock solid even when the picture behind it It also
doesn't occur at all when we watch something through the S-Video port.

My first thought was that it was something in the tuner...but I've
been told that it could be AGC or something between the tuner and the
sync separator.

The second problem is with the actual picture (when it is steady).
There are several bands on the screen, about an inch wide, where the
picture appears to be smeared to the right. The bands can get worse/
better depending on what image is on the screen or what channel it is
on. There is also a band that is almost always there, where about the
top 10% of the screen is pushed to the right (it increases in the
amount pushed right as you go towards the top of the screen, if that
makes sense).

I have no idea what causes this problem.

Can anyone help? I may be able to take a quick video of the problems,
if needed.

Thanks,
Neil

 

[Chuck]

On Thu, 13 Nov 2008 06:04:01 -0800 (PST), "neil.tuttle@gmail.com"
<neil.tuttle@gmail.com> wrote:

Hello!

We recently got a nice big TV for free (from the trash) and it has a
couple problems that I would like to fix!

Mitsubishi CS-31301C

The first problem is the most annoying...the screen rolls from bottom
to top. It will do this very fast, sometimes it's so fast it just kind
of flickers. It only occurs on some channels, or at least is only very
BAD on some channels, and is definitely worse when the TV hasn't been
used for a few hours (it's cold). It doesn't effect the OSD at all -
the OSD stays rock solid even when the picture behind it It also
doesn't occur at all when we watch something through the S-Video port.

My first thought was that it was something in the tuner...but I've
been told that it could be AGC or something between the tuner and the
sync separator.

The second problem is with the actual picture (when it is steady).
There are several bands on the screen, about an inch wide, where the
picture appears to be smeared to the right. The bands can get worse/
better depending on what image is on the screen or what channel it is
on. There is also a band that is almost always there, where about the
top 10% of the screen is pushed to the right (it increases in the
amount pushed right as you go towards the top of the screen, if that
makes sense).

I have no idea what causes this problem.

Can anyone help? I may be able to take a quick video of the problems,
if needed.

Thanks,
Neil

Most of the problems are caused by many high esr and leaking
electrolytic capacitors. If this model has the pip board with surface
mount capacitors replace them all or bypass the board. I would buy an
esr meter and look for black crud underneath the electrolytic
capacitors. The Rubycon caps failed more than the other brands Mits
used. Finally, clean the circuit board where the caps leaked. I've
had horizontal shimmy or lack of vertical sync caused by electrolyte
on the board after cap failure. Chuck

 

[Trendal]

Well I have taken the thing apart...but on first visual inspection, I
can find nothing at all wrong with it. All the caps appear fine, with
nothing leaking out or bulging tops. Aside from a little dust, it
appears to be in good condition! (not bad for a curbside pickup!)

Anyway, here's a couple quick pics I took as well as a lint to the
service manual. Can anyone point me in the right direction? I do have
a scope, if need be.

http://i359.photobucket.com/albums/oo37/trendal/IMG_06871.jpg
http://i359.photobucket.com/albums/oo37/trendal/IMG_06881.jpg

http://www.eserviceinfo.com/download.php?fileid=31941

thanks!