Odd crt... wierdness

tester007

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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?
 
with the game off, is there still 120vac bieng sent to the monitor? if so, mabye thats why the old monitor died. a monitor running 24/7 is a bad bad idea for alot of reasons. With the game off, there should not be power to the monitor. I could see the dots thing happening mabye if it was getting power still with the gameboard and everything else off.

as far as getting the pic to look correct with a wei ya chassis, good luck. they tend to look marginal at best. Keep adjusting and tinkering, you should be able to get it to an acceptable comprimise.
 
The power runs into the game into a box with a standard white pressure switch activated by the back door that you can pull out to lock on for power. From there it is filtered and fuse in box, out to a switcher i put in. I tap off the 120 input to the switcher point to go to the monitor (since it does not need an isolation transformer) and to the marquee light. So when i put the white switch back in all power is cut off to the cab. I can even unplug it and spots like that will glow for a couple minutes or more.

This crt came fom a different cab so i dont know how it was abused before but the crt face looks like new.

P.s. Aside from not getting a very black background level with the chasis, i am very happy with the pic.. Convergence as well is right on which is why i would hate to have to take all this off and throw a go7 chasis on and have to try and reconverge it. But i am really at a loss as to what is causing that..
 
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