Wave Guide Cover Replacement - TurboChef NGC (Tornado) Service Manual

24 THE MICROWAVE SYSTEM
Prior to fully energizing the Microwave Circuits,
the Control energizes the Filament Transformers
for approximately three (3) seconds prior to
supplying the necessary high voltage via the High
Voltage Transformers. When in operation, the
Filament Transformers supply approximately 3.15
VAC at 10 Amps to each Magnetron Filament.
The Filament Transformers are controlled via
the K1 Relay.
F3 Fuse (P/N 100599)
The F3 Fuse is a 20 Amp Class CC fuse designed
to blow in the case of an over current scenario, such
as a High Voltage Transformer or Capacitor failure.
The Fuse also blows if the Monitor Circuit trips
the failsafe.
High Voltage Capacitors (P/N 100201)
Their rating is 0.91uF, 2500 VDC.
High Voltage Diodes (P/N 100481)
They are rated at 16 kVDC.
Monitor Relay (P/N 101271)
The Monitor Relay, K3, acts as a failsafe device in
the High Voltage Circuit. In its normal un-energized
position the Monitor Relay shorts L1 and L2. If the
K2 Relay energizes the High Voltage Transformers
while the K3 Relay is un-energized the F3 Fuse
will blow.
Magnetron Thermostats (P/N 102070)
The Magnetron Thermostats are an open on rise
type thermostat. These Thermostats are designed
to open at 212 º F.
   : Both Magnetron Thermostats are wired
in series. Therefore, if one opens the Control will
switch off both Magnetrons until the Thermostats
close. The Thermostats are self-resetting.
Magnetron Cooling Fan (P/N 100083)
The Magnetron Cooling Fan supplies cooling air
for both Magnetrons. The Fan operates at 208/240
VAC and is controlled via the K1 Relay.
Wave Guide Covers (P/N NGC-1097)
Wave Guide Covers protect and seal the Wave
Guides from moisture and debris.
WAVE GUIDE COVER REPL ACEMENT
The Wave Guide Covers keep moisture and debris
out of the Wave Guides. If contamination gets into
the Wave Guides, the life of the Magnetrons may
be shortened. In most cases, the Wave Guides will
not be contaminated if the Wave Guide Covers are
cracked or broken - it depends on how long they
have been cracked and how much product has been
cooked. However, if a Magnetron has failed and the
Wave Guide Cover is cracked, the Wave Guide may
need to be removed and either cleaned thoroughly
or replaced.
Figure 17 details the removal and replacement of
the Wave Guide Covers. To remove the Wave Guide
Covers, follow the steps below:
1. Locate the fourteen (14) #8 truss head sheet
metal screws securing the broken Wave Guide
Cover. If the screw heads are dirty, it will be
necessary to clean the heads thoroughly.
      : Do not strip the screw heads.
2. Spray screw heads with a penetrating oil such as
WD 40 and allow them to sit for a few minutes.
3. Remove the fourteen (14) #8 screws using a
good #2 Phillips Screw Driver. The cover should
come loose with gentle pressure.
    remove the two (2) right and left
x
most screws. These screws secure the Wave
Guides to the oven floor. Only remove them
if the Wave Guide is being removed as well.
4. Remove the old Wave Guide Cover and discard,
unless otherwise specified.
   : It may be necessary to gently pry the
Wave Guide Covers to remove them from the
oven floor as they are sealed with RTV.