Bought this game for personal collection with a problem on the RED colour which was completely missing.

Checking the schematics there are some 74541 chips which are sending the colour bits to a resistor network for Dac conversion. The one on the red colour @UC4 was correctly working so I checked the 74ls07@UA4  involved in the blanking circuit.

Pin 2 was always below 0.5V  and muted the total red colour

After changing it I restored the red colour