In Hardware

I must say, after browsing the site I see how I can fix at least a couple of problems with my original NES unit (it flickers half the time, locks up mid play, etc) but I would also like to fix a unit I picked up at a thrift store (unfortunately I can only use one of the two units as the one I picked up at the store had no POWer... suppose I could pick up a new one)

Anyway, unit number two only displays black and white. I swear it played in color at some point in time, but it doesn't anymore. I even tried Hooking up RCA cables instead of the Nintendo cables, still black and white. I briefly got unit one working to know it's not my TV or the games.

Anyone have any suggestions?

The only thing I can think of, and this only comes to mind because my SNES likes to fool me this way sometimes, is that you have the NES switched to Channel 4 and the TV on Channel 3. If, however, it's a hardware problem, well. I have no ideas.

hmmm... I'm not really sure. I think the SMS3 has a problem displaying in different regions. It shows up in black-and-white I believe because it's PAL-M. Is there a chance that it may be an NES from a different region? I wouldn't know how to go about checking that, maybe seeing if the bottom of the unit says anything different (volt usage and mA maybe?). I'm just guessing though.

That's a possibility.

I was thinking that maybe the Y (Luma) and C (Chroma) signals had gotten separated (broken trace on the board or something...), but that's impossible, as the PPU outputs composite directly.

the region difference sounds like the most likely problem.

Thanks for the replies!

Last night before I posted I tested both channel 4 and channel 3 (moved the switch and changed channels on my tv) and just tried it again to make sure, and that didn't work.

I compared the bottoms of the two units to one another and they're identical as far as all the markings go (except serial number obviously). Also, if it were a PAL unit, wouldn't that mean it wouldn't play my NTSC games? (It is unmodded)