Need some help about ms-2930

For monitor related issues
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huluhala
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Need some help about ms-2930

Post by huluhala »

Image
I don't know how to discribe the problem in English. :cry:
I know the crt is ms-2930 because of the remote board.
update:I upload a new image about it.
Image
Last edited by huluhala on November 29th, 2021, 1:30 pm, edited 1 time in total.
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nem
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Re: Need some help about ms-2930

Post by nem »

My guess is a magnet / magnets have fallen off from the yoke. That's some bad geometry.
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PrincessPrinPrin
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Re: Need some help about ms-2930

Post by PrincessPrinPrin »

Looks like vertical foldover: the top of the picture (left side in this case as the screen is mounted vertically) bends down so the top half of the circles becomes concave. Not sure why the bigger circle doesn't show the same distortion. Maybe try a tighter test pattern that covers all areas. If this is the issue there is a cap near the vertical deflection IC that is bad. If the 2930 has a LA7846 like the 2931 the cap is the one connected to pin 8:
LA7846.jpg
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huluhala
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Re: Need some help about ms-2930

Post by huluhala »

PrincessPrinPrin wrote: November 29th, 2021, 12:31 pm Looks like vertical foldover: the top of the picture (left side in this case as the screen is mounted vertically) bends down so the top half of the circles becomes concave. Not sure why the bigger circle doesn't show the same distortion. Maybe try a tighter test pattern that covers all areas. If this is the issue there is a cap near the vertical deflection IC that is bad. If the 2930 has a LA7846 like the 2931 the cap is the one connected to pin 8:

LA7846.jpg
Thanks, I'll try it if I have a chance.And I upload a new image.
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nem
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Re: Need some help about ms-2930

Post by nem »

PrincessPrinPrin wrote: November 29th, 2021, 12:31 pm Looks like vertical foldover: the top of the picture (left side in this case as the screen is mounted vertically) bends down so the top half of the circles becomes concave.

Oh wow, didn't even think of that. Nice catch!
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grantspain
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Re: Need some help about ms-2930

Post by grantspain »

yep looks like it, la7838 on 2930 chassis but could be one of the caps causing this
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