Brightness problem MS-2930

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LarsVegas
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Brightness problem MS-2930

Post by LarsVegas »

I have a brightness issue with my MS-2930 monitor. Tweaked the rgb, brightness and contrast pods already, but the picture is to dark in the blacks and to bright overall and in the white areas in the same time. Feels like, when warmed up, it's getting better, but still far from good. Does a cap kit help or is something else causing this problem?

Greets Lars
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nem
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Re: Brightness problem MS-2930

Post by nem »

Adjust SCREEN pot on the back of the flyback.
Sbdesign
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Re: Brightness problem MS-2930

Post by Sbdesign »

yea screen pot should sort it, on the flyback with the focus pot.

It could still do with a service, but try the suggestion first.
Get it warmed up where its at its best, and adjust the brightness, contrast to the middle value.
Adjust the screen pot to the desired brightness, and fiddle again with the other pots.
LarsVegas
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Re: Brightness problem MS-2930

Post by LarsVegas »

Ok, thanks guys. I will try it. When I tweaked the cut-offs and brightness, it looked ok. So I didn't touch the screen pot. There is a topic in the wiki and I will follow this. Will post the result.
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Re: Brightness problem MS-2930

Post by LarsVegas »

I try to get into this crt stuff, cause you f keeping those alive as long as possible. So I came around one other thing. Tried those convergence strips and on one side the deflection coil had more space to put those strips in. The convergence on this side was more off. Can you move the coil to improve convergence too? Didn't found something about this.
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Re: Brightness problem MS-2930

Post by Ioncannon »

I assume moving the yoke? Moving the yoke will change your purity (back/forward) and rotate the screen itself. The convergence rings on the back of the yoke can be adjusted for convergence with strips.

Moving yoke is for fixing issues like this:
LarsVegas
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Re: Brightness problem MS-2930

Post by LarsVegas »

Ok. But it does not fix Corner conversion, just discoloration?
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Re: Brightness problem MS-2930

Post by zumbito »

Any updates on this? I'm interested too.
LarsVegas
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Re: Brightness problem MS-2930

Post by LarsVegas »

I will adjust the screen pot on Sunday. I won't make it before.
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Re: Brightness problem MS-2930

Post by LarsVegas »

So, tweaked the screen pot, brightness, cutoffs and gains. The screen pot was nearly good. It is looking much better, but not like my 2931. But I can live with it for now. It's depending on the PCB as well. Mushihimesama looked pretty good, cps-2 not so, it's much brighter. Last solution cap-kit?
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grantspain
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Re: Brightness problem MS-2930

Post by grantspain »

only a couple of caps would affect brightness, the 10uf 250v on the neck card would be a culprit- watch out for those cap kits and certainly do not replace the large orange 4.7uf as it will be most likely the wrong type in the kit

another possibility could be that the chassis has been replaced on this in the past and the resistor for the heater current is wrong value
LarsVegas
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Re: Brightness problem MS-2930

Post by LarsVegas »

Ok thanks Grant, I will check this cap out. When I have all the tools for discharge, I will give it a shot. The geometry on this monitor is crap to i realized yesterday, even with tweaking the pots with pincushion, etc. Pots. Convergence seems to get sorted out by strips, but the tube needs a good clean in the yoke area first. Guess it's getting a project for this summer.
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Re: Brightness problem MS-2930

Post by nem »

LarsVegas wrote:
April 11th, 2021, 10:10 pm
Last solution cap-kit?
Your last solution is to rejuvenate the tube. I did it with a Blast tube and got good results out of it.
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Re: Brightness problem MS-2930

Post by LarsVegas »

With rejuvenate, you mean a new tube?
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nem
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Re: Brightness problem MS-2930

Post by nem »

No, you use a rejuvenator on your old tube.

https://blog.timowens.io/crt-rejuvination/

May or may not give lasting results.
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Re: Brightness problem MS-2930

Post by LarsVegas »

Ok, I get it. Looked for one on the internet, but they are hard to come by and I don't think, that the screen is to dim overall. I can boost the colors and brightness, but the overall level is not right. It's more like a contrast thing, where the whites and darks drift away. So you have too bright or too dark.
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