Service Manual for
RCO Speed Oven
36
OVEN FRONT
Secondary
Interlock
Switch
Secondary Interlock Switch –
Left Side of Oven
CAUTION:
The monitor relay needs to be replaced
after a malfunction of the interlock sys-
tem that causes the fuse to Open.
Monitor Circuit Test
The Monitor circuit protects against hazardous
microwave leakage by disabling the oven if a fault
exist in the microwave system with the oven’s door
open or ajar.
Tools Required
Option 1
• Jumper Wire
• Test Fuse Jumper Harness
Option 2
• Digital Multimeter
Test Procedure
Option 1:
This procedure provides a functional check
of the monitor circuit.
1. Remove the oven from its power source.
2. Remove the top panel to gain access.
3. Disconnect wire ORN H1 from the Mains Terminal
Block ‘L1.’ This will insure that the heaters do not
come on for the balance of the test procedure.
4. Disconnect wire WHT 99 COM 1 and BLU 85 from
the Voltage Relay. This will insure no power to the
high voltage transformers.
5. Connect the jumper wire between wire WHT 99
and the Mains Terminal Block ‘L1.’
6. Disconnect BLK L1 from the Line Supply side of
the Fuse Block.
7. Connect the Test Fuse Jumper Harness between
the Fuse Block and wire BLK L1.
8. With the door closed, reconnect the oven to its
power source.
9. The controller and cooling fans should be operating.
NOTE:
This next step should cause the Test Fuse
to trip and verifies proper monitor circuit function.
10. Open the door. Verify that the Test Fuse trips and
remove the oven from its power source.
11. Rewire to the original configuration.
a. Remove the jumper wire between wire
WHT 99 and the Mains Terminal Block ‘L1’.
Reconnect wire WHT 99 to COM 1 and BLU 85
to COM 2 on the Voltage Relay.
b. Remove the Test Fuse Jumper Harness
between the Fuse Block and wire BLK L1 and
reconnect wire BLK L1 to Line Supply side of
the Fuse Block.
c. Reconnect wire ORN H1 to the Mains Terminal
Block ‘L1.’
12. Reinstall top panel.
Option 2:
This procedure provides a continuity check
of the monitor circuit.
1. Remove the oven from its power source.
2. Remove the top panel to gain access.
3. Disconnect wires WHT 99 COM 1 and BLU 85 COM
2 from the Voltage Relay contacts. This prevents
the microwave circuit from being powered.
4. Disconnect WHT 98 at the Mag SSR “T1” and
connect WHT 98 with BLK M1 to the “L1” screw
terminal on the Mag SSR. This provides the monitor
trigger source for verification testing.
5. Unplug wire WHT 97 from Mains Terminal Block
‘L2.’
6. Connect Voltage Meter test leads to the WHT 97 wire
and the open connection on the Terminal Block ‘L2.’
The following steps 7. and 8. measurements confirm
proper monitor circuit action.
7. Close the oven door and plug in the unit. The meter
should read zero volts.
8. Open the oven door. The meter should read line
supply voltage (208/240V~).
9. Unplug the unit’s line cord.
