IBM EGA 5154 Monitor - too bright?

[offensive_Jerk]

I've got this 5154 that seems to be very bright. When you turn the brightness all the way down, its like the picture goes darker, but the raster stays illuminated. With the brightness all of the way down, you can still see some of the game on the screen in this video.

I've talked with other 5154 owners and this is not normal. Anyone know what would cause this, or how to fix it? I don't think its ever been serviced. Would a capacitor cause this or something else? Just an adjustment?

I should add that I don't see the problem on this page for this monitor.
http://minuszerodegrees.net/video/Mo...0Database.html

https://youtu.be/cSJidMPWkgw

[Trixter]

I think you're confusing the brightness knob with the contrast knob.

[offensive_Jerk]

I think you're confusing the brightness knob with the contrast knob.

No, its at the end of the video.

[Trixter]

Okay, had to watch it with sound so that I could understand what you were doing, since without sound it looks like the monitor is working perfectly. So, yes, the black level is supposed to decrease when you turn the brightness all the way down. So, some of your components are failing. The good news is that a capacitor replacement will likely fix the issue.

[offensive_Jerk]

Here’s a better video

[Trixter]

Yes, that needs recapping.

[pcdata76]

I'd decrease the screen (G2) control on flyback transformer first before recapping the monitor. It could be misadjusted by its previous owner for some reason.

[Stone]

It's also possible that the flyback itself is shot.

[offensive_Jerk]

I adjusted the flyback control... no immediate difference was noticed, but.... I left the computer and monitor on for about 90 mins and the issue went away. Seems to go away when the unit warms up. I turned it off and on but the monitor was warmed up and didn’t do the brightness raster thing... I’m guess omg it will happen again when starting the monitor cold.

[pcdata76]

I adjusted the flyback control... no immediate difference was noticed, but.... I left the computer and monitor on for about 90 mins and the issue went away. Seems to go away when the unit warms up. I turned it off and on but the monitor was warmed up and didn’t do the brightness raster thing... I’m guess omg it will happen again when starting the monitor cold.

Then probably some of the caps in the video and CRT drive sections are high in ESR and need to be replaced. ESR goes down with increasing temperature in electrolytic caps and symptoms disappear.