MX4000 Picture with black stripes

4 replies
B(
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BerndE (archived)
Bronze
Posted November 28, 2009 at 12:02 GMT
#1756421

Hello Beoworlders,

a few weeks ago my MX4000 (model 7870 from 1998) started to have black stripes and shadows in the picture. The stripes are not always visible, so it seems to be a slack joint or a dying component. This is how the picture looks like:

 

A soft knocking on the top of the black back cover of the TV solves the problem, but the stripes come back after a few minutes.

The stripes also appear in teletext and external AV sources.

I have seen the MX4000 workshop (http://forum.beoworld.org/forums/p/24571/191760.aspx#191760), but i am not sure if my problem is related to the fixes in the workshop.

 

Thanks for any tips

Bernd

 

N(
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nobby (archived)
Bronze
Posted November 28, 2009 at 14:19 GMT
#1756422

Looks like a problem on the vertical deflection ... most probably that 2.2uF cap in the drive line.

T(
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trigi (archived)
Bronze
Posted January 30, 2010 at 06:06 GMT
#1756423

Hi

Replacing the caps C131 and C134 , 470uf 16v use to solve this problem.

Best regards

Trigi

(Denmark)

B(
Offline
BerndE (archived)
Bronze
Posted March 8, 2010 at 14:00 GMT
#1756424

I finally found some time to recap the mainboard as described in the link. A complete success 🙂

The problems with the picture are gone and I'd say the picture is now as good as new.

A good source for the low ESR caps is the .

Bernd

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