Microwave Circuit
9-5
Microwave Circuit Defective Messages SELF TEST WHILE COO KING CAUSE CORRECTIVE ACTION
LOW MAG CURR
*HV BREAKDOWN
F3 MAG CURR
* European ovens
only
LOW MAG CURR
*HV BREAKDOWN
F3 MAG CURR
Note:
If this message is
detected while
cooking it will
terminate cook
cycle immediately.
Oven CT1 (computer board
current sensor) did not
detect current to the
magnetron transformer.
Notes:
1) Magnetron must be ON
to detect current in circuit.
2) If main circuit breaker
keeps tripping for no
apparent reason, check hi-
limit switch, monitor relay,
heater, mag ssr operation.
1. Check main internal circuit
breaker. .If tripped, check the
following operation:
a) Cook Door Switch
Misalignment (Chpt. 7)
b) Magnetron transformer
(Page 9-8)
c) Hi limit switch (Page 8-2)
d) Heater Failure (Page 8-2)
e) Shorted diode
2. Check operation of the monitor
relay (door operation).
3. Check input current to K4-1
wire. Microwave circuit measures
approximately 9 Amps. If higher
than 15A replace anode
transformer (See 9-8).
4. Check diode
5. Check capacitor
6. Check magnetron
7. Check ssr operation
8. Filament Transf ormer
9. Current Transform er on
computer board. See Page 6-
10
MAG OVER TEMP
F5 MAG TEMP
MAG OVER TEMP
F5 MAG TEMP
Note: If this
message is
detected while
cooking it will
terminate cook
cycle immediately
Oven software detected
Magnetron thermostat
open. Implying the
magnetron case
temperature is above 212˚F
(100˚C), therefore opening
switch and canceling
magnetron operation or
loose connection.
1. Check Magnetron Thermostat
for loose wires.
2. Check for proper operation of
magnetron blower (Note:
Magnetron fan only operates only
when magnetron is energized and
remains on for 3 minutes after
magnetron is turned off).
3. Check for loose wiring in the
circuit.
4. Check magnetron fan relay for
proper operation.