Hello,

We own a Toshiba 2877DB television which has recently developed an intermittent horizontal frame collapse problem.

A while back, I noticed a feint white line bouncing at the bottom of the screen.

About a week ago, it developed the frame collapse problem. I checked for dry solder joints around the H. Output transistor (Q404) and also re-soldered some of the connections in the horizontal output section that looked dull.

The TV subsequently worked for a few days but then the same problem again. I have re-soldered the connections to the LOPT and some other components in the horizontal output section area. Unfortunately, the problem is now worse!

I have searched for common fixes but nothing comes up that is relevant for the TV. Some sites mention a frame IC (TA1241) needing to be replaced for this model however, I couldn't locate it on the schematic?

I'm wondering if one of the capacitors may have dried up?

I have uploaded the schematic to the following site, hoping that someone can offer some advice:

http://www.filefactory.com/file/agh1...-3377_C7SS_pdf

Thanks.

"M.Joshi" wrote in message
...

Hello,

We own a Toshiba 2877DB television which has recently developed an
intermittent horizontal frame collapse problem.

A while back, I noticed a feint white line bouncing at the bottom of
the screen.

About a week ago, it developed the frame collapse problem. I checked
for dry solder joints around the H. Output transistor (Q404) and also
re-soldered some of the connections in the horizontal output section
that looked dull.

The TV subsequently worked for a few days but then the same problem
again. I have re-soldered the connections to the LOPT and some other
components in the horizontal output section area. Unfortunately, the
problem is now worse!

I have searched for common fixes but nothing comes up that is relevant
for the TV. Some sites mention a frame IC (TA1241) needing to be
replaced for this model however, I couldn't locate it on the
schematic?

I'm wondering if one of the capacitors may have dried up?

I have uploaded the schematic to the following site, hoping that
someone can offer some advice:

http://tinyurl.com/owzkku

Thanks.




--
M.Joshi



Obviously, the vertical output IC needs to be resoldered, as well as the
yoke connector plug at the main board. The IC, probably the TA1241 you
mentioned, will resemble a small audio amp IC on a heat sink, not too far
from the yoke plug.

Additionally, Toshibas are notorious for bad capacitors in and relating to
the vertical section.


Mark Z.

On Thu, 14 May 2009 01:51:10 +0100, M.Joshi
put finger to keyboard and composed:

We own a Toshiba 2877DB television which has recently developed an
intermittent horizontal frame collapse problem.

A while back, I noticed a feint white line bouncing at the bottom of
the screen.

About a week ago, it developed the frame collapse problem. I checked
for dry solder joints around the H. Output transistor (Q404) and also
re-soldered some of the connections in the horizontal output section
that looked dull.

You should be checking the vertical section, not the horizontal.

I have uploaded the schematic to the following site, hoping that
someone can offer some advice:

http://tinyurl.com/owzkku

Check frame IC Q301 (TA8427K) for dry solder joints. Also check R305.
Replace the electrolytic capacitors in that area.

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

Update:

I replaced a couple of the small-value electrolytic capacitors around the frame output IC Q301 (TA8427K):

C320 (100µF)
C305 (1µF)

I also re-made some of the solder joints in that area.

The TV worked OK for a day with the white horizontal line still bouncing at the bottom of the screen. However, it has the frame-collapse problem again. Tapping the TV recovers it!

I will try re-soldering the frame output IC and coil connections.