TurboChef i3 Service Manual

OVEN SYSTEMS
27
Microwave System
The i3 oven employs left and right microwave sys-
tems. In the case of an over-current situation, the F3
fuse will blow, shutting off both systems immediately.
This section contains information about the
following components:
- Capacitors
- Filament transformers
- High-voltage diodes
- High-voltage transformers
- Magnetrons
- Stirrer motor and assembly
- Waveguides
This section also contains procedures for:
- Testing a capacitor
- Wiring the filament transformers
- Testing a high-voltage diode
- Wiring the high-voltage transformers
- Testing a filament or high-voltage transformer
- Testing a magnetron for an open/shorted
filament
For information on accessing and removing parts, see
the Appendix.
Capacitors
- Capacitor rating is 0.91uF, 2500 VDC for all
60 Hz installations (except Japan).
- Capacitor rating is 1.15uF, 2500 VDC for all
50 Hz installations.
- Capacitor rating is 0.85uF, 2500 VDC for
60 Hz Japan installations.
Testing a Capacitor
DANGER: Never attempt any measurement
of the capacitors while they are enabled.
Lethal voltage will be present. Measure only
in compliance with these procedures.
1. Disconnect the oven from the power source.
2. Remove the top cover of the oven.
3. Fully discharge the capacitor.
4. Isolate the capacitor from the circuit.
5. Check for an open or shorted capacitor by placing
ohmmeter leads between the capacitor terminals:
- Rising/escalating ohm readings = capacitor OK
- Constant infinite resistance = capacitor open
- Constant very low resistance = capacitor
shorted
6. If the capacitor is not open or shorted, set the
meter to measure capacitance and again place
the leads between the capacitor terminals. The
meter reading should equal the label value, plus
or minus 10%. If not, replace the capacitor.
Filament Transformers
For better operation and reliability, the oven
uses separate transformers in order to preheat the
magnetron filaments.
The control energizes the filament transformers for
approximately five seconds prior to energizing the
microwave circuit via the high-voltage transformers.
When in operation, the filament transformers supply
approximately 3.15 VAC at 9-10 amps to each
magnetron filament. The filament transformers are
controlled via the K1 relay.
Wiring the Filament Transformers
DANGER: Never attempt to measure the
secondary voltage values of the filament trans-
formers when they are connected to the mag-
netron circuit. Lethal voltage will be present.
The installation of filament transformers is straight-
forward. Filament transformers are wired in-phase and
in-line. Refer to the schematic on page 49, detailing
the proper wiring.
To verify correct wiring (North America),
measure the voltages between terminals
1&2and 1&
3
on FT1 and FT2. The voltages must be 208 and
240 VAC respectively.
Continued on page 28.

TurboChef i3 Specifications

General

Model	i3
Cooking Chamber	Stainless Steel
Cavity Dimensions	14.5 x 16 x 10 inches
Power Requirements	208-240V, 30A
Control Type	Touchscreen