RAINBOW COLORS ON SCREEN; PICTURE TUBE BASED TELEVISIONS
This
fault appears on picture tube based televisions are due to low EHT
[Extra High Tension} voltage from the LOT [Line Output Transformer] or
[Fly back Transformer]. There are mainly two cusses for this. The first one is with the high voltage rectifying diodes. These
diodes are within the LOT itself, and will be sealed; and no
replacement can be done. If the fault is with these diodes/diode; there
is no other way than replacing the LOT as a unit.
The second possibility is with the free wheeling capacitors. Replace the capacitors connected to the collector of the horizontal output transistor to negative ground point. There will be a capacitor with high voltage ratings. Replace the yolk return capacitor too. If these do not help, replace the Line Output Transformer