Atari2600 4Switch NTSC RCA displays Black & White on EURO TV

[retroborg]

Good day!

I have an Atari 2600 4-Switch Darth Vader NTSC PCB CO15519 REV 16 (C) 1980



On which I performed the Composite RCA AV Mod as described in this Link:

http://retro.mmgn.com/Atari-2600/Forums ... 600-AV-Mod

I specifically used the following components and connected them to 2 RCA Jacks as I did on my other PAL Atari 2600 4-Switch console.

"Green TIA Pin 2 (Sync): Direct to video
Yellow TIA Pin 5 (Lum 1): 1k Resistor
Yellow TIA Pin 6 (Lum 2): 220 ohm Resistor
Yellow TIA Pin 7 (Lum 0): 1K Resistor

Red A is for Audio
Blue C is for Color

Pins A and C don’t need any components but you can use\should put a 100p ceramic capacitor on Blue C. Both A and C will then go directly to you RCA jack's."

Everything works fine and the display is much clearer in relation to the RF output without distortions, however both the RF & RCA output only display in black & white on my EURO CRT 21" SONY TV KV-21FQ10 which is more than capable of display in in colour at 60HZ as it suppots PAL-60 and all my other modded consoles play fine on it with color via RGB Scart.

Is this natural because this is an NTSC console, or is it something which I’ve done wrong, or is there a problem with this specific console?
I note that the RF Output displayed in black & white even before I performed the RCA mod, but I thought it would be OK with RCA.

By the way, this specific PCB has this weird circuit enclosed in a huge plastic block like a brick, which is connected on various points on the PCB which I do not recognize their use. I have no idea of its purpose nor have I ever seen anything similar before.

I considered removing it, but decided not to in case it replaces / fixes some defective components or IC on the PCB and has been added as an external fix.

Could this be causing the black & white display?

http://s1356.photobucket.com/user/retro ... t=3&page=1

Any help will be highly appreciated
Thanks in advance

[Hobie-wan]

Well, does your TV accept NTSC signals? I know feeding PAL to an NTSC TV results in a B&W rolling screen, so I'd expect more or less the same if anything on a TV that's only expecting PAL.

[retroborg]

Well, does your TV accept NTSC signals? I know feeding PAL to an NTSC TV results in a B&W rolling screen, so I'd expect more or less the same if anything on a TV that's only expecting PAL.

Well an NTSC Commodore 64 & NTSC Commodore VIC-20 which I connected via an RCA AV Composite cable directly from their video factory outputs (Not modded), worked fine with colour on this specific TV. However an NTSC Sega Genesis II console which I connected the same way via RCA (Not modded) also dislpayed in black & White.

[Hobie-wan]

Ok, I dunno then.

[ApolloBoy]

However an NTSC Sega Genesis II console which I connected the same way via RCA (Not modded) also dislpayed in black & White.

It could be that your TV is super picky about the color subcarrier signal used by those consoles, even some NTSC TVs are like that as well. Do you have a different TV you can try it on?

[retroborg]

So, it would seem there was a much easier solution. I simply rotated the pot on the PCB a few degrees and the color magically apeared!
With some trial & error I settled at a spot where all my games look ok, with color on my TV. However the colors do look a bit different compared to the other Atari 2600 consoles I've modded.

Thanks for the info none the less!

By the way, does anybody have the slighest idea what that huge block of hard plastic encloses inside and why it's connected on to the PCB?!

I would like to X-Ray it!

[ApolloBoy]

However the colors do look a bit different compared to the other Atari 2600 consoles I've modded.

That pot you adjusted is for the color adjustment, try adjusting it a little more until you get the tint where you want it to be.

By the way, does anybody have the slighest idea what that huge block of hard plastic encloses inside and why it's connected on to the PCB?!

Looks like the previous owner's attempt at an AV mod, what an absolute hack job. If your AV mod doesn't interfere with it, I'd say remove it.