NES with bad color - fixable?

[freewheel]

Hey guys - there seem to be a lot of technically-adept folks at AA so I figure I'll give this forum a shot.

 

I have an original NES-001 that refuses to output the color red. Is this something that is easily repairable and I'm just clueless? From poking around over the years I get the impression that RGB isn't exactly easy to isolate on the mainboard, ie: the PPU doesn't even output it as separate signals. Which leads me to believe that the PPU is bad on this deck.

 

Am I wasting my time poking around? If it was a bad trace or cap, it's something that's easily fixed, but I assume that the color signals aren't isolated on the board from what I've read. And no, this isn't a bad connector or dirty cart issue Just a lack of red in the video signal, both RF and Composite.

 

Thanks!

Edited July 7, 2014 by freeweed

[ifxbr]

Hey freewheel, same problem here. Did you have any progress?

 

I am trying to investigate the problem, but it seems bad PPU.

Check the schematics at http://console5.com/wiki/Nintendo_NES-001.

Also we have the PPU pinout here: http://wiki.nesdev.com/w/index.php/PPU_pin_out_and_signal_description.

 

You are right: there is no R, G and B separated signals, just VOUT at PPU pin 21.

Please update me if you can solve it... Lets share information.

 

Thanks!