Videonics Equalizer (VE-1) RGB colorizer issue - looking for help on fix

[doodark]

Hello,
I've got two videonics equalizers from the US that both have an issue with the colorizers. The colorizer sliders should tint the entire image, but although they do change the image, it appears only more faded or darker in grayscale. There's no change of colour whatsoever.

Demo video i took of the issue: https://www.youtube.com/watch?v=mY1y_uKgavY&feature=youtu.be
How it should be functioning: http://www.infinitelooper.com/?v=bdmWLlMfA5s&p=n#/57;104

I've checked I am using the right USA to UK transformer and polarity etc, so its definitely an internal issue.

Can anyone could give me some pointers on what might need replacing in terms of parts (see pic of internal)? OR point me in the direction o a video hardware electronics repair service in London, UK?

Ive included some pics of the circuit board..  Any help much appreciated

[Alex Eisenhut]

errrmmm... that's a NTSC box? You're in the UK? Are you feeding in NTSC video? You sure the colorburst is at the right frequency?