stays lit while heating uo but then fashes wen at the right tempurature which is really anoying i would like it the other wsay round its a yihua 937d its a cheap copy of an hakko anyone please help thank you
regards
rick

 

You can't unless you modify the circuit, the led is across the heater, and is controlled by a triac, when heating it's on, and when at temperature the triac is pulsed by the integrator to maintain the set temperature .