Galaga Graphic Issue

1iblind

Well-known member

Donor 4 years: 2012, 2015, 2017, 2019
Joined
Jul 30, 2012
Messages
1,822
Reaction score
73
Location
Albuquerque, New Mexico
The game plays great and all of the sounds and everything work but I have these darn blue lines going everywhere. Any idea what may be causing this? Thanks in advance!
 

Attachments

  • IMG_20161102_1411367.jpg
    IMG_20161102_1411367.jpg
    200.6 KB · Views: 54
Can't see the starfield. Starfieldgenerator-IC 05xx faulty?
What happens if you remove it?
 
Yes, I can see the starfield doing what it's supposed to. Should I still try removing IC 05xx?

If you remove 05xx at the socket you need to ground pin 20, otherwise you don't get any display ( it's connected to Chip Select of the final color output PROM ).
 
The lines are static.

Ok, the fact that the lines appear to be on every other scan line and the text looks fine over the top of the lines ( text with color has priority over sprites on the Galaga hardware ), I'd be looking at the the sprite RAM. Either eight 2147 or two 2148 depending on what's populated on the board. Also possible the 74LS296 at 5B, also make sure the resistor pack at RM5 isn't damaged or cracked.
 
Ok, the fact that the lines appear to be on every other scan line and the text looks fine over the top of the lines ( text with color has priority over sprites on the Galaga hardware ), I'd be looking at the the sprite RAM. Either eight 2147 or two 2148 depending on what's populated on the board. Also possible the 74LS296 at 5B, also make sure the resistor pack at RM5 isn't damaged or cracked.

Thanks jrok! I'll try your suggestions out.
 
Back
Top Bottom