Sony multisystem KV k29MF1 rescued but that need a lot of work on the picture

[Benyamin39]

Hi,

I am now working on the CRT adjustment and this TV has a lot of issues. I have done quite some study on the web and I went through the service manual but I am left with a few questions, mainly on dynamic convergence and white balance

I mainly followed the service manual instructions sequence and steps.
https://drive.google.com/file/d/1IiC...ew?usp=sharing

Beforehand I reset all service menu settings to default (and recorded the previous settings).

Beam landing
I checked on the Beam landing. The purity is very good (Green / Red / Blue) so I did not have to adjust the deflection yoke.

The beam does not reach the right side of the Tube. The service manual does not mention anything about it, so I chose to simply adjust on the service menu shift to center the picture and then hsize to stretch it. If I should have done otherwise let me know.
https://drive.google.com/file/d/1ZL9...ew?usp=sharing

Static convergence
The next step is the static convergence. I believe it is pretty decent (at least compared to the dynamic convergence, white balance and geometry issues). I only adjusted H-stat slightly. I did not touch the rings. Here Below is a picture. Somehow the red beam is thicker than the blue beam and green beam (probably my white balance issue, see further down…)
https://drive.google.com/file/d/1VuD...ew?usp=sharing


Dynamic convergence

The dynamic convergence is terrible
The blue is offset to the right (both left and right side of the picture)
On the top part of the screen the blue is above the red on the left side and below on the right side.

I tried first to tilt the yoke vertically and horizontally (a few degrees max) but nothing really changed. and I think it was already adjusted when snugged to the 3 wedges. This being said I found 2 issues.

1.When I loosened the yoke 3 pieces of paper with material inside fell. It looks like the material is not magnetic. What were they for?
https://drive.google.com/file/d/1Yad...ew?usp=sharing

2. I flipped out of the yoke all the magnetic strips. The picture did not change. I opened one strip and the magnet inside is very small but still magnetic. What is happening here?
[before removing the strips, well ... picture is not very clear, white appears blue, the picture taken after geometry adjustment is of better quality and tell the same story]
https://drive.google.com/file/d/13mm...ew?usp=sharing
[IMG="before removing the strips"]https://drive.google.com/file/d/13mm4DcCdeyXC8HzCJNRr5HhxlDROlahm/view?usp=sharing[/IMG]
[after removing the strips]
[IMG="after removing the strips]https://drive.google.com/file/d/13nG2wrJrTIFBI4vrqAr8U4g3JiDRTIRS/view?usp=sharing[/IMG]
https://drive.google.com/file/d/13nG...ew?usp=sharing

3. From your experience do you think this level of convergence issue can be fixed by using new strips (I started to play with home made strips using "home depot" magnets strips), or did I miss something when adjusting the yoke instead?



G2 adjustment and white balance adjustment
The white balance is terrible, the white is pinkish and the black is greenish.

Following the service manual again, I started by adjusting the G2 Varistor (RV701) and I think there is a problem there. Using a multimeter I read KR/KG/KB 150V/103V/150V. Should they not be the same voltage?
Furthermore looking at the electronic diagram the indicated voltage is about 160V
Reading the service manual, the recommended value is 185V. I tried and KG would ramp up to only 112V. Which one is to be followed?
For the time being I left it at the original settings.

White balance
I can’t get the white balance right. Following the service manual instructions I setup the blue and green cut and drive. I had to push the green drive to the maximum and the sub bright adjustment to the minimum, and still the color balance is bad. The image is also dim. What is the issue there?

Geometry
This TV has a ton of options from the service menu to adjust geometry distortion. It turns out that setting the right geometry for most areas was straightforward. I played with the yoke to align the picture as well. Maybe I should have adjusted the geometry first. I am left with the bottom of the screen for which nothing can be done using the service menu. Would magnet be able to solve this level of misalignement at the bottom?
https://drive.google.com/file/d/13a7...ew?usp=sharing


Thanks for your help

[Benyamin39]

I have checked on resistors and diodes. They display proper values.
I tested for cold solder without finding any.

I have traced the voltage level on the transistors of the neckboard with a multimeter (attached is a picture of the measurement). It seems the problem is from the Transistor Q702 on the green line.

the transistor is operating but does output a lower voltage than what the one on the red line is doing. Is this component the source of the problem and have a weak behavior?

https://drive.google.com/file/d/17VT...ew?usp=sharing