2600 game colors on 7800 system

[jjh76]

Moving this here so I don't clutter up the UAV thread.

 

I recently bought a 7800 from a local retro shop, after checking that it was working I went and installed Bryan's UAV and one of his audio companion boards. Unfortunately, before doing the mod I didn't pay attention to the colors on the 2600 games I used to check it so I don't know if what I'm seeing now is how it looked originally or if I messed something up when doing the mod.

 

When I installed the UAV I left the RF modulator intact, and I'm getting the same colors from the RF out as I do through the UAV's composite out. For the composite out on this one I've got the UAV hooked up to a trrs port which can do composite+audio from a single jack. All tests were done on a crt tv with the picture settings on standard.

 

Aside from Tower Toppler, which I'm told uses artifacting for colors that doesn't work right when using composite out, I have three 7800 games that I can use to adjust color: Pole Position II, Dig Dug, and Karateka. Although there are some slight color differences from the screens shots I've seen of these 3 games, they are very minor and I'm satisfied with the color setttings for the Maria pot.

 

However, for 2600 colors I've tested several games, checking them against the colors on my light sixer. I've adjusted the TIA color pot to get it as close as I can, but although some colors look correct, other colors don't. This is most noticeable in Ms. Pac-man with the cherries being the correct shade of red, Ms Pac and the ghosts appear to be the correct colors, but the maze walls are a almost flesh-tone instead of purple and the blue of the playfield is a dark navy blue instead of the lighter blue I see on the sixer. If I turn the pot clockwise just a little the maze does get a little more purple, but so do the cherries, the playfield turns completely black and the ghosts turn green when you eat a power pellet. If I go the other way I can get the playfield to nearly the same shade of blue as the sixer, but then the maze turns nearly yellow.

[+-^CrossBow^-]

Okay...few things here to talk about. The artifacting in Tower Toppler should still work and look correct when using composite out on a CRT. LCDs will try to handle this, but likely will generate odd rainbow like banding or possibly the wrong colors completely. As for the 2600 color adjustment, Pitfall is a good one to use, however it is again important to note that only on a CRT will the colors actually look correct with any of these mods. I've used all the mods available at one time or another for the 7800 and so far Bryan's UAV has proven to be the best all around for me and the 3 or 4 7800s I've modded using his Rev. D board. I haven't installed the UAC into one yet as mine already uses the filter cap method off the north ends of the r5 and r6 resistors and I've not had any other 7800s come my way to mod since I got the UACs to compare with.

[jjh76]

But tower toppler looks almost completely different - pics snapped off my crt tv, first is from the RF out, second one is composite from the UAV:

 

A little hard to see with these, but the character sprite, the platforms, and the bottom strip of water are the same color from both outputs, but the tower,the highlights on the edges of the platforms, and some parts of the water are completely different, almost like all the blue color was turned off just for those graphics, leaving only the red component.

 

This is the only game that this happens with, my 3 other 7800 games and all the 2600 games I've tried show the exact same colors through either output. Which would be fine if the purple colors on some of the 2600 games wasn't so washed out.

[bigbacon]

With my 7800 hooked up to a non crt tv i had tovadjust the tint for the colors to be right.

 

Im am composite.

 

Composite on a crt was no problem.

[jjh76]

Well, blame it on bad soldering. Bumped the UAV and the wire that connects to location 0 on the UAV detached from the leg of the resistor I had soldered it to. Put it back on and added a little extra solder to the other wires. It's not perfect, but the colors look much better now. Except for Tower Toppler, which still has red where it should be blue/purple

[Trebor]

...It's not perfect, but the colors look much better now. Except for Tower Toppler, which still has red where it should be blue/purple

 

Tower Toppler utilizes a 320 mode of the 7800 which can display Color Artifacting. The now red, which was previously blue/purple, is not an uncommon side effect. Video hardware modifications, as well as the type of hardware display being utilized, may influence the results of color artifacting.

 

As taken from the 7800 8BitDev site's Color Artifacting section, notice the different results captured from the 7800 console, 320 mode, color artifacting:

 

The aforementioned site provides direction on how game programmers can minimize artifacting; regardless, Tower Topper does contain a relatively high amount of color artifacting.

[+H454]

Your light sixer may have the 820 resistor mod done (or built in?). The colors (warmer colors especially) look much more vibrant.

 

This thread goes into detail-

http://atariage.com/forums/topic/241317-improved-color-for-your-4-switch-woody-a-public-service-bulletin/

The 5th post has some good screen shots of the color differences.