CRT TV:What causes this kind of geometry issue?

[GraphicMan]

Hello
anybody knows what is responsible of producing this kind of geometry issue? in an LG 29" flatron crt tv?

thanks

[R_J]

Re: CRT TV:What causes this kind of geometry issue?

could be a bad one of these, scope the vertical circuit

[eccerr0r]

Re: CRT TV:What causes this kind of geometry issue?



Well with flat CRT screens a lot of magic is needed to make sure that things are lined up. A lot of the times a microcontroller has a setting to control parallelogram alignment and a slight misadjustment may look like that...

But yes a bad one of those things ^^ could cause it too...

[GraphicMan]

Re: CRT TV:What causes this kind of geometry issue?

wow a bad cap may cause that?
i am almost sure that this is a new thing to the tv, i did not notice it before
i want to add also that that tv has a lot of enlarged areas when it is bright

meaning if there is a wide bright strip in the screen like a white wide cnn news bar, that area is kind expand wide and cause deformation, is that fixable or it depend on the tv model?!!

[eccerr0r]

Re: CRT TV:What causes this kind of geometry issue?

There are a lot of strange controls needed to control a flat screen short neck CRT versus a traditional long neck curved screen.

/_/ and \_\ parallelogram control
/_\ and \_/ trapezoid control
(_) and )_( barrel and pincushion control

You'll have to supply a photo to describe.

[R_J]

Re: CRT TV:What causes this kind of geometry issue?

Why not post the model number so we know what we are dealing with. An actual picture of screen with the fault might help also.

meaning if there is a wide bright strip in the screen like a white wide cnn news bar, that area is kind expand wide and cause deformation, is that fixable or it depend on the tv model?!!

Check when there is a large white area is there bleading of a color(R,G,B,) to the right of the white area? If there is it could be the crt is weak.
Does lowering the contrast or brightness help ?
You may also have a power supply problem, When there are large white areas on the screen, that demands more current from the power supply, If this happens the voltage can drop or the pwm circuit gets noisy causing lines etc. on the screen.

Is this a HD tv, check it with a different resolution and different input.

[GraphicMan]

Re: CRT TV:What causes this kind of geometry issue?

no it is not an HD tv
it is RT-29FB75VE

no there is no bleeding when the white areas expand wide
i dont think the crt is weak because the colors, contrast and sharpness is really good (better than most new led tv's)
lowering contrast or brightness have no effect on this phenomena
my other sony 21" crt tv make it too but in a much smaller manner

I have played ALOT in the service secret menu, and i was able to adjust the screen through the time to its best ever possible state
however there are a LOT of other functioned in it that I dont understand what does it make and it seem not making any difference although its wide range of choice (0 to 2000!!!)

let me share these menus
please dont judge the vertical lines from these pics as it is not clear with so many details