tester007
Well-known member
I have a Korea A1 monitor where the flyback blew. The crt looks like new so I picked up a Wei-ya chassis for it and got it running. Picked up a Frogger board and got it all running for my Frogger resto. But it does a couple odd things.. so far I have rejuved it to not much change, and for all 3 guns I cannot get any cutoff level to register.. not sure if this affects below..
1st odd thing is when the game is shut off, there are 4 or so fuzzy diamonds in the center of the screen about 1 - 2 inches wide each of red, green, blue, and I think a yellow one. Its like the electrons are still being shot at the screen even after the game is off. The diamonds can glow on the screen for a few minutes.. anyone see this before or know what causes it? I took a pic but don't have the phone in front of me at this moment.
2nd thing I cannot fix is it seems the monitor has the brightness turned up just a bit too high all the time.. not for the colors, but for the background.. I can dial in the colors and they are fantastic... but the black areas always look like the brightness is turned up just passed the best point.. there are also some vertical distortion lines in that brightness. Now for some odd reason on the Wei-ya chassis they have doubled up every control.. there is a brightness on the pcb as well as the flyback so I only use one or the other. I 'can' get the black areas of the screen to black only one way, and its not via the brightness. If I turn down the brightness to get black, all colors are gone as well, but even then its not really completely black. To get it so, I need to turn the 'screen' focus pot on the flyback. It only goes to black when I take the focus out of focus a bit. If I then turn up the brightness to get color, it looks ok but slightly soft. If I dial up the focus again to be sharp (and man is it good and sharp), then I get the slightly greenish/yellow blacks with the vertical lines (these lines are very faint, but certainly noticeable).. anyone know if there is a black level on the wei-ya chassis or anything that could fix this? I really would like to be able to keep this crt..
Is this crt being driven too hard and the phosphors are being excited too much causing both issues?
1st odd thing is when the game is shut off, there are 4 or so fuzzy diamonds in the center of the screen about 1 - 2 inches wide each of red, green, blue, and I think a yellow one. Its like the electrons are still being shot at the screen even after the game is off. The diamonds can glow on the screen for a few minutes.. anyone see this before or know what causes it? I took a pic but don't have the phone in front of me at this moment.
2nd thing I cannot fix is it seems the monitor has the brightness turned up just a bit too high all the time.. not for the colors, but for the background.. I can dial in the colors and they are fantastic... but the black areas always look like the brightness is turned up just passed the best point.. there are also some vertical distortion lines in that brightness. Now for some odd reason on the Wei-ya chassis they have doubled up every control.. there is a brightness on the pcb as well as the flyback so I only use one or the other. I 'can' get the black areas of the screen to black only one way, and its not via the brightness. If I turn down the brightness to get black, all colors are gone as well, but even then its not really completely black. To get it so, I need to turn the 'screen' focus pot on the flyback. It only goes to black when I take the focus out of focus a bit. If I then turn up the brightness to get color, it looks ok but slightly soft. If I dial up the focus again to be sharp (and man is it good and sharp), then I get the slightly greenish/yellow blacks with the vertical lines (these lines are very faint, but certainly noticeable).. anyone know if there is a black level on the wei-ya chassis or anything that could fix this? I really would like to be able to keep this crt..
Is this crt being driven too hard and the phosphors are being excited too much causing both issues?