Sony Trinitron 19" Flat CRT persistent magnetising stain on corner / excessive bright

[rfsapiens]

Hello people,

I've got a very nice Sony Trinitron HMD-A420 CRT 19" Flat Screen with very good and very sharp image but it has a problem which it's the fact of getting persistent magnitising yellow stain on the lower right corner which turns the image in that corner yellowish and "decolourized".
When I shut down the CRT and turn it on again the degauser works and the picture stays clear and perfect for a while but after a minute or so that corner begans to yellow and loose a bit the color again. If I get a speaker magnet closer to that area of the monitor becomes clear again until I take the magnet out...
Also I tried to pass gently in circle motion the speaker magnet and it worked for a while but after some time specially after just turning off the CRT and on after a few minutes the symptoms return to the same spot... Probably I'll have to permanently put a magnet on its side :/
Is there anyway to permanently solve this issue instead of having to put magnets on the CRT?
Also I have another issue with this screen which is excessive brightness and I need to find a way to adjust the brightness to correct values (which is excessive even on zero since the blacks are simply grey) I read somewhere you need some programs, a special cable or to cut a resistor. Can anyone give me an help / guidance with this? Also I need to turn down a bit the red gun on the blacks (although the colors are good and correct the blacks tend to be a bit red).
I think this CRT is still good but how can I fix this thing? I would like to get it fixed to offer it to my mom

With the best regards,

Rfsapiens.

 

[rfsapiens]

Any Idea of what can I do with this?

Regards.

 

[therealnickdanger]

You just described several problems that may or may not be related. It could be EMI or you could have a failing gun or a failing controller or any combination of those. If I were you, I would get a cheap/free LCD off Craigslist... that is, if you really love your mom. Why make her lift/move such a heavy monitor?

As to the EMI (electromagnetic interference) distortion on the screen, do you have a subwoofer near or under the desk? When I still had my FW900, it was affected by my subwoofer from 10ft away. Try testing the monitor in another room away from other EMI sources. It might be permanently damaged. It's possible that you could make yourself a homemade degausser (or buy one) to attempt a fix, but who's to say the problem won't return?

Try a different cable. It probably won't fix anything, but just try it.

Color balance issues or brightness settings you'll have to use the monitor's calibration tools to resolve that, perhaps even use alongside the settings of your graphics card. If the tube is at its life's end, then there is nothing you can do - nothing cheaper than buying an LCD anyway (or taking someone else's CRT).

Sorry if that's not much help, but I recently went through a similar trauma with my FW900. Even though I still miss it sometimes, I don't regret moving to LCD.

 

[Puffnstuff]

Well if degaussing the monitor doesn't work you might try a local repair shop if you really want to save it. I used to have a G400 and it was a really fine monitor back in the day but for what ips lcd's cost these days I'd just dump it.