LyonsArcade
Well-known member
Hi folks!
I've got a G05-801 in an Asteroids I'm working on, I've narrowed this problem down to the monitor. The power supply and board work fine on an oscilloscope display, and the board works in another cabinet, and another board in this cabinet provides the same problem.
So basically when it comes on, the bottom line of the test menu is skewed up out of where it should be. Notice the background crosshatch is fine... in gameplay, you can't tell as easily what's going on but that bottom line of text is skewed up the same, and when asteroids get down in that area on the bottom right they don't look right. After about 5 minutes, the line eventually moves across the screen, and lays down into place where it should be. So it's only messed up for the first 5 minutes it's on.
So I believe it's a problem in the Y deflection (it seems to be deflecting x properly but the y value is off)... I've replaced the bottlecap transistors on the chassis, recapped and reflowed everything, checked the voltages coming from the regulator board (-25, +25), checked the values of all the resistors in the y section and couldn't find any out of spec, replaced the TIS98's in the y section, replaced the U07's... replaced the two zener diodes in the Y section... i'm to the point where i'm just randomly shotgunning stuff.
Anybody ever seen one do this, or can figure out logically why it's doing this?
I've got a G05-801 in an Asteroids I'm working on, I've narrowed this problem down to the monitor. The power supply and board work fine on an oscilloscope display, and the board works in another cabinet, and another board in this cabinet provides the same problem.
So basically when it comes on, the bottom line of the test menu is skewed up out of where it should be. Notice the background crosshatch is fine... in gameplay, you can't tell as easily what's going on but that bottom line of text is skewed up the same, and when asteroids get down in that area on the bottom right they don't look right. After about 5 minutes, the line eventually moves across the screen, and lays down into place where it should be. So it's only messed up for the first 5 minutes it's on.
So I believe it's a problem in the Y deflection (it seems to be deflecting x properly but the y value is off)... I've replaced the bottlecap transistors on the chassis, recapped and reflowed everything, checked the voltages coming from the regulator board (-25, +25), checked the values of all the resistors in the y section and couldn't find any out of spec, replaced the TIS98's in the y section, replaced the U07's... replaced the two zener diodes in the Y section... i'm to the point where i'm just randomly shotgunning stuff.
Anybody ever seen one do this, or can figure out logically why it's doing this?
