T-FXPAKUC 1206.3 + SamyGO
It works without gnd because you HAVE gnd from pc to tv from earth gnd on the 220v power plug... This is very dangerous for your tv /pc (chips ports)
Gnd could be connected also on VGA metal case only...
Try swap rx and rx, might it helps. Or probably you soldered bad contact for rx. I made such mistake also, my rx was on gnd It took a while until I found problem ...
But if TV is 5 series, you have to enter another code to unlock console. Might for plasma code is like this also?