PC Engine and Core Grafx repairs

[Ergot_Cholera]

I just got a PC Engine and Core Grafx that were described in the listing as not powering on. The PC Engine did power on but had glitched graphics.
 I opened it up and found that one of the RAM chips was absolutely covered in flux, so I removed it but found that the chip was actually stuck to the board with all the excess flux.I replaced the chip with a new one and.......it works perfectly now! I was surprised and elated.

The Core Grafx did not power on. I replaced the fuse and it works but the video is bad, not bad like glitches but the image is wavy and the colours are mixed up, plus sometimes it would go from colour to black and white.
I tested the Core Grafx with a Tennokoe 2 that I have modified for RGB which uses pure sync and the image is perfect, so there is obviously something wrong with the composite video output. Could it be something to do with the 470uF capacitor? Should I try pin 40 of the HuC6260?