R-334 (serv.man4). Complete - Sharp Home Appliance Service Manual (repair manual). Page 11

R-334 - 11

ASYMMETRIC RECTIFIER
The asymmetric rectifier is a solid state device that prevents
current flow in both directions. It prevents the temperature
rise of the power transformer by blowing the special fuse F1
when the high voltage rectifier is shorted.

The rated peak reverse voltage of D1 of the asymmetric
rectifier is 6 KV. The rated peak reverse voltage of D2 of the
asymmetric rectifier is 1.7 KV. D1 and D2 of the asymmetric
rectifier or high voltage rectifier are shorted when the each
peak reverse voltage goes beyond the each rated peak
reverse voltage.
(The process of blowing the fuse F1)
1. The high voltage rectifier is shorted by any causes when

microwave cooking.

2. The peak reverse voltage of D2 of the rectifier goes

beyond the rated peak reverse voltage 1.7 KV in the
voltage doubler circuit.

3. D2 of the rectifier is shorted.
4. The large electric currents flow through the high voltage

winding of the power transformer.

5. The large electric currents beyond 8A flow through the

primary winding of the power transformer.

6. The fuse F1 blows by the large electric currents.
7. The power supply to the power transformer is cut off.