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.