This failure shows that can pull the main relay contacts can be closed RY1 oven lamp is turned on and the motor circuit , but not heated because:NJhservice manual download site

( 1 ) door monitoring switch S3 is damaged, contact ablation bad or no electricity , so light tubes and high-voltage transformer circuit H barrier , leading to heating . Use a knife to scrape the ablation fouling S3 , S3 contacts can make a good conduction.NJhservice manual download site

( 2 ) the diode D7, R20 resistance becomes large, resulting in the transistor Q13 base voltage is low, so that Q13 is not turned on , thereby cutting off the base of Q6 circuit so Q6 off causes light relay, the relay can not be energized by microwave absorption together, so light tubes H, high voltage transformer circuit is not connected, it is not heated ; or transistor Q13, Q14 breakdown open, Q6 same deadline , light , microwave relay can not pull . RY2, RY3 is not closed , the heating circuit is switched off. Replace these damaged components can troubleshooting.NJhservice manual download site

( 3 ) resistor Rll, R12, R13 resistance becomes larger or open ; press the start key , Q6 of hopping around the base voltage is less than 1.2V, or 06 base open circuit ( off ) , so 06 is not turned on . Q5, Q4 collector circuit is cut off , Q5, Q4 is not conducting , light , can not pull the microwave relay contacts RY2, RY3 can not be closed , the light pipe H, the microwave system does not work , it is not heated. Replace damaged resistors troubleshooting.NJhservice manual download site

    ( 4 ) transistor 06 Breakdown ( open ); Dl0 resistance becomes larger . Resulting press the start key , e voltage 06 can not jump to 2.5V or less , are so light, microwave relay not normally pull . Replacing 06 or Dl0, can troubleshooting.NJhservice manual download site