Sony KV-9200 Uneven Raster

[Alex KL-1]

Originally Posted by vol.2

So I found that the boost voltage derived from the Horizontal Yoke pulses is quite a bit too high. In order to get the width to cover the whole screen, I end up with close to 600V boost, when I am supposed to be getting around 500-530V.

When I changed the width, it changes the boost voltage, and the boost voltage feeds the G2, which is why changing the width also changes the brightness.

I don't really understand this. Is it by design?

Should the loading on the boost rectifier determine its voltage? And if so, should it be this wide of a margin?

You can see here where the boost is created. I assume it's rectifying the H yoke pulses as there is no other source I can see.

This circuits are very tricky and interactive ideed; no much ideas, but...
Compensation of bright according with beam current or even H size is seen. But, if so, the circuit responsible for that was...?
Is easy to see how H size reduced have more bright due to less area for same total beam distribution.
Something are definitively interacting and playing havoc. It must be in a circuit that controls the sweep current, but where?

Even T502 can cause havoc but with such symptoms, something are draining more current with smaller size perhaps?