[Tom9589]

I just got through doing a side-by-side comparison between the Kuba schematic and an HC Porta-Color. There is one Compactron in the Kuba set: the 1AD2 high voltage rectifier. There is a lot of similarity in the circuits, even down to the same value of components. The RF, IF and horizontal are very similar. The vertical is somewhat different. Kuba even uses the color oscillator crystal ringing circuit that GE seemed to exclusively use. They even have a screwdriver adjust for tint.

The main difference is the PAL color demod circuit. They still use the diode pair demods that GE uses though.

I would love to see one of the Kuba sets in operation after owning two Porta-Colors.

I suspect that Compactrons were is short supply in Europe so Kuba decided to use equivalent European tubes which accounts for the Kuba set having four more tubes. It also could have been a royalty issue against using the Compactrons. However, considering how much Kuba was already paying GE for all the other components, you would think that GE would have thrown in the Compactrons for free.

One more interesting thing. The power supply choke is tapped. It looks like they may be using it as an auto-transformer to get a little (~ 10V) boost for the +275 V supply. I suspect this may be common practice for a 220VAC TV with a simple half-wave rectifier circuit.