NESRGB in original Famicom, red color missing.

I just installed a NESRGB with P/A board in a friends Famicom. Install went good, and looks pretty nice. This is the tenth one I've done (all NES-models included), but also the first time I've had any problems.

I get perfectly sharp video and audio just fine, but the red color is completely missing :/

Naturally I suspected the RGB cable to be bad, but there is continuity from the NESRGB straight to the SCART plug, so that's not the problem either.

My soldering is good, and I've checked continuity between the PPU and motherboard, as well as check if the traces on the Famicom were broken during the desoldering, that doesn't appear to be the case.

I found this thread on shmups about missing greens:
http://shmups.system11.org/viewtopic.php?f=6&t=51425

In that case one of the 220uF capacitors were faulty, but I tried swapping them around and that's not the case here either.

I suspect the NESRGB to be faulty. But is there anything I should try before I contact Tim Worthington about it?

 

Check the NESRGB for solder splashes. I thought mine was faulty as my NES wouldn't load games from my Everdrive and there was artifacts on the Everdrive menu. Turns out I had accidentally bridged 2 pins on the main chip on the NESRGB with a tiny splash of solder. Obviously it must have happened when I was soldering the wires to the NESRGB.

 

That's a good suggestion, but that wasn't it