For anyone new searching...I had a similar problem. Turns out the main power connector was slightly corroded. Been battling this issue on and off for years and changed almost all the parts trying to nail it down. A little sand paper a she's going strong again!
It's the main power connector. About 8-10 pins. All yellow and red wires. Located on the circuit board attached to the heater. Follow the red and yellow wires of the transformer.
It's the main power connector. About 8-10 pins. All yellow and red wires. Located on the circuit board attached to the heater. Follow the red and yellow wires of the transformer.