Turbo Chef Technologies Residential Single and Double Wall Oven Magnetron Failure, Blower Failure

Magnetron Failure

A current transformer located on the control board monitors the current draw of the microwave system. The oven uses two separate magnetron circuits, each drawing approximately 8-9 amps. If the control board senses 0 amps, this error screen is displayed.

Possible causes:

-Faulty K3 or K4 relay (Gen 1) or relay 2 or 3 (Gen 2; the entire relay board must be replaced)

-Faulty left or right high-voltage transformer

-Faulty left or right high-voltage capacitor

-Faulty left or right high-voltage diode

-Faulty left or right magnetron

-Faulty 20-amp fuse (Gen 2: located on relay board as F1 fuse)

-Faulty wiring

-Faulty control board

-Faulty left or right magnetron thermostat

Possible components to be replaced:

-K3 relay (Gen 1) or relay 2 or 3 (Gen 2; the entire relay board must be replaced)

-K4 relay (Gen 1) or relay 2 or 3 (Gen 2; the entire relay board must be replaced)

-High voltage transformer

-High voltage capacitor

-High-voltage diode

-Magnetron

-20 amp fuse (Gen 2: located on relay board as F1 fuse)

-Control board

-Left or right magnetron thermostat

Magnetron Failure Troubleshooting

1.Pull the oven 11” (280 mm) from the cabinet and remove the top front cover.

2.Place the oven in Installer Setup mode (page 4.4).

3.Place a water load in the cook cavity.

DANGER: DO NOT touch or attempt to mea- sure the magnetrons, HV transformers, capacitors, or any component within the microwave circuit while the magnetrons are running. Lethal voltage will be present.

4.Turn the magnetrons on and measure for 15-19 amps around the wire in the current transformer loop on the control board.

5.Turn the magnetrons off. Depending on the measurement, follow the below steps.

If 15-19 amps are present, verify the magnetron cooling fans are running whenever the magnetrons are running. The thermostats can cause the magnetrons to shut down and reset when cool.

If 8.5-10 amps are present,

1.Check relay operation. For Gen 1, check the control voltage from the control board at P8-13 + P8-5, and at P8-14 + P8-5. For Gen 2, visually check relays 2 and 3 for operation. If they operate correctly, check the HV outputs to each transformer at terminals RBJ-4 + RBJ-5.

2.Isolate the left and right magnetron circuits and retest. For Gen 1 ovens, remove the brown lead to the transformer. For Gen 2 ovens, remove either RBJ-4 or RBJ-5.

If 0 amps are present,

1.Ensure power is reaching the oven from the wall.

2.Check the 20-amp fuse.

3.Check for incoming voltage at each transformer when the magnetrons are energized. For Gen 1, test voltage from the relays at the transformer.

For Gen 2, 208 or 240 VAC must be between the blue wire at the CT coil (CT1-B) and either terminal RBJ-5 (right) or RBJ-4 (left) on the relay board.

Blower Failure

The control board sends voltage to the blower motor speed controller (BMSC) to activate the blowers. If both blowers successfully activate, a signal is sent back to the control board to verify the system is functioning normally. If that signal is not sent back to the control board, this error screen is displayed.

Possible causes:

-BMSC (blower motor speed control)

-Blower motors

-Faulty control board

-Faulty wiring

-Faulty relay board (Gen 2 only)

Possible components to be replaced:

-BMSC

-Blower motors

-Control board

-Relay board (Gen 2 only)

6.3

TROUBLESHOOTING