(1) If the 9-pin RS flip-flop input is low, it may be open to R810, RT2 damage, R808 open, C805 S102 contacts breakdown or leakage, Q802 internal damage; (2) by S101, RS flip-flop 13 no low pulse input pin, mostly poor contact contact S101; (3) RS flip-flop output of 11 feet is always low, mostly Q801 internal damage or pin desoldering open; (4) R814, R811 , Q812 open, D804 breakdown leakage, RY02 open coil or contacts poor contact.kwtservice manual download site