Faint red/purple "haze" in left corners

[emuola]

Noticed this just the other day. My BVM20F1E has just noticeable (depends on the color displayed, light blue border color of C64 is a suitable background) faint red/purple haze in both left corners. The area is really small, appr. 1 cm2 (~0.4 inch2) and really does not have any real effect to use, but I just want to make sure if there's something to worry about here.

I noticed that adjusting the rotation setting affects the visibility of the problem.

Is this something to worry about? Monitor has been recapped by a pro a year ago. Geometry etc. are perfect, nothing to complain here.

[Taiyaki]

When you rotate do the patches rotate proportionally to how the rest of the picture rotates or do they just jump around? I had a couple BVM's of that line up but the G series instead of F. The BVM should be degaussing each time you power on so it's probably not a magnetic interference problem, just my guess though but it sounds like a color purity issue. I had one with something similar in that the whites were not pure white and showed some color (iirc in my case was some yellow), it was also towards the edges. I never did manage to get it fixed but someone more knowledgeable might have some advice.

When I had a serious problem on one it stemmed from the power supply board. I popped it out and replaced it with another one from ebay and it fixed a problem (heavy loud buzzing). In this case sounds like something on the deflection board.

[NoAffinity]

Degaussing needed possibly?

Sent from my SM-G955U using Tapatalk

[emuola]

When you rotate do the patches rotate proportionally to how the rest of the picture rotates or do they just jump around? I had a couple BVM's of that line up but the G series instead of F. The BVM should be degaussing each time you power on so it's probably not a magnetic interference problem, just my guess though but it sounds like a color purity issue. I had one with something similar in that the whites were not pure white and showed some color (iirc in my case was some yellow), it was also towards the edges. I never did manage to get it fixed but someone more knowledgeable might have some advice.

When I had a serious problem on one it stemmed from the power supply board. I popped it out and replaced it with another one from ebay and it fixed a problem (heavy loud buzzing). In this case sounds like something on the deflection board.

When I rotate the screen, the patches grow/get more purple or get smaller/less purple "proportionally", e.g. rotating upper left corner "upwards" makes the patch get smaller in the lower left corner and grow in the top left corner and vice versa. I hope this makes sense

.

Degaussing needed possibly?

Sent from my SM-G955U using Tapatalk

The Sony degausses itself on every boot, so that should not be the problem. I also tried to manually degauss it as it has the button for that in the "remote controller"

*edit*

I tested with Core Grafx 240p suite and the convergence is really good, near perfect. Also when I tried the different full screen color tests of 240p suite (R,G,B, White and Black) I could not see the haze even when the screen was blue. Then again I can see the haze with 2 different computers, namely C64 (RGB mod) and MSX2 (native RGB out), because the background color of the Basic screen of both computers is "light blue". How can this be? CoreGrafx and MSX2 both use the same input card and inputs + the whole signal path, so that cannot be the reason. It seems there's purple haze with light blue and no purple haze with darker blue.

is this completely insane, what I'm describing here? :O