larrylemming
Member
I've been working away at a Galaxian cocktail for a while now. I finally got it to play (bad CPU and RAM were the culprit) but it's still having some issues.
Specifically, the video is a little bit funky. On first glance, it looks like I'm losing the least significant bit of the vertical count, but I know that I'm not because I checked it and it's fine. The starfield is fine, and oddly enough most of the invaders are fine. It's mainly in the characters where it's seen.

I replaced 2H-2L according to the Galaxian troubleshooting guide, but no such luck. ROMs both seem to check out fine as well (I recently replaced all the EPROMs.)
2 major questions:
1. Which way does the monitor scan (i.e. should I be looking for problems in the horizontal or the vertical control circuitry?)
2. Any suggestions on common culprits? The picture is stable, just not quite right.
Specifically, the video is a little bit funky. On first glance, it looks like I'm losing the least significant bit of the vertical count, but I know that I'm not because I checked it and it's fine. The starfield is fine, and oddly enough most of the invaders are fine. It's mainly in the characters where it's seen.

I replaced 2H-2L according to the Galaxian troubleshooting guide, but no such luck. ROMs both seem to check out fine as well (I recently replaced all the EPROMs.)
2 major questions:
1. Which way does the monitor scan (i.e. should I be looking for problems in the horizontal or the vertical control circuitry?)
2. Any suggestions on common culprits? The picture is stable, just not quite right.