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Toshiba 2877DB - Int. frame collapse

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:

formatting link

Thanks.

--
M.Joshi
Reply to
M.Joshi
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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.

Reply to
Mark Zacharias

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

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

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

- Franc Zabkar

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

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.

--
M.Joshi
Reply to
M.Joshi

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