Klasse KOC-154K User manual

Service Manual
Microwave Oven, Convection & Grill
KOC-154K
SEP. 2008

1
PRECAUTIONS TO BE OBSERVED BEFORE AND
DURING SERVICING TO AVOID POSSIBLE
EXPOSURE TO EXCESSIVE MICROWAVE ENERGY
(a) Do not operate or allow the oven to be operated with the door open.
(b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other
microwave source, and make repairs as necessary: (1) Interlock operation, (2) Proper door closing, (3)
Seal and sealing surfaces (arcing, wear, and other damage), (4) Damage to or loosening of hinges
and latches, (5) Evidence of dropping or abuse.
(c) Before turning on power to the microwave oven for any service test or inspection within the microwave
generating compartments, check the magnetron, wave guide or transmission line, and cavity for proper
alignment, integrity, and connections.
(d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave
generation and transmission systems shall be repaired, replaced, or adjusted by procedures described
in this manual before the oven is released to the owner.
A microwave leakage check to verify compliance with the Federal performance standard should be
performed on each oven prior to release to the owner.
TABLE OF CONTENTS
1. SAFETY AND PRECAUTIONS....................................................................................................................................2
2. SPECIFICATIONS ........................................................................................................................................................3
3. EXTERNAL VIEW.........................................................................................................................................................3
3-1. OUTER DIMENSION..........................................................................................................................................3
3-2. FEATURE DIAGRAM .........................................................................................................................................4
4. INSTALLATION............................................................................................................................................................5
5. CONTROL PANEL .......................................................................................................................................................6
6. DISASSEMBLY AND ASSEMBLY..............................................................................................................................7
7. INTERLOCK MECHANISM AND ADJUSTMENT.....................................................................................................18
8. TROUBLESHOOTING GUIDE...................................................................................................................................19
9. MESUREMENT AND TEST .......................................................................................................................................25
9-1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT........................................................................25
9-2. MICROWAVE RADIATION TEST....................................................................................................................26
9-3. COMPONENT TEST PROCEDURE................................................................................................................27
9-4. COMPONENT ACTION....................................................................................................................................28
10. WIRING DIAGRAM...................................................................................................................................................29
11. EXPLODED VIEW AND PARTS LIST ..................................................................................................................31
11-1. DOOR ASSEMBLY.........................................................................................................................................31
11-2. CONTROL PANEL ASSEMBLY.....................................................................................................................31
11-3. TOTAL ASSEMBLY........................................................................................................................................31
12. PRINTED CIRCUIT BOARD ....................................................................................................................................35
13. P.C.B CIRCUIT DIAGRAM.......................................................................................................................................39

2
1. PROPER USE AND SERVICE PRECAUTIONS
1. FOR SAFE OPERATION
Damage that allows the microwave energy (that cooks or heats the food) to escape will result in poor cooking and may
cause serious bodily injury to the operator.
IF ANY OF THE FOLLOWING CONDITIONS EXIST, OPERATOR MUST NOT USE THE APPLIANCE. (Only a trained
service personnel should make repairs.)
1) A broken door hinge.
2) A broken door viewing screen.
3) A broken front panel, oven cavity.
4) A loosened door lock.
5) A broken door lock.
The door gasket plate and oven cavity surface should be kept clean.
No grease, soil or spatter should be allowed to build up on these surfaces or inside the oven.
DO NOT ATTEMPT TO OPERATE THIS APPLIANCE WITH THE DOOR OPEN.
The microwave oven has concealed switches to make sure the power is turned off when the door is opened.
Do not attempt to defeat them.
DO NOT ATTEMPT TO SERVICE THIS APPLIANCE UNTIL YOU HAVE READ THIS SERVICE MANUAL.
2. FOR SAFE SERVICE PROCEDURES.
1. If the oven is operative prior to servicing, a microwave emission check should be performed prior to servicing the
oven.
2. If any certified oven unit is found to servicing, a microwave emission check should be performed prior to servicing the
oven.
(a) inform the manufacturer, importer or assembler,
(b) repair the unit at no cost to the owner,
(c) attempt to ascertain the cause of the excessive leakage,
(d) tell the owner of the unit not to use the unit until the oven has been brought into compliance.
3. If the oven operates with the door open, the service person should tell the user not to operate the oven and contact
the manufacturer immediately.
CAUTION
MICROWAVE RADIATION
PERSONNEL SHOULD NOT BE EXPOSED TO THE MICROWAVE ENERGY WHICH MAY RADIATE
FROM THE MAGNETRON OR OTHER MICROWAVE GENERATING DEVICE IF IT IS IMPROPERLY
USED OR CONNECTED. ALL INPUT AND OUTPUT MICROWAVE CONNECTIONS. WAVEGUIDES
FLANGES AND GASKETS MUST BE SECURED. NEVER OPERATE THE DEVICE WITHOUT A
MICROWAVE ENERGY ABSORBING LOAD ATTACHED. NEVER LOOK INTO AN OPEN WAVEGUIDE OR
ANTENNA WHILE THE DEVICE IS ENERGIZED.
CAUTION
This device is to be Serviced only by Properly Qualified Service Personel. Consult the Service Manual for Proper
Service Procedures to Assure Continued Safety Operation and for Precautions to be Taken to Avoid Possible
Exposure to Excessive Microwave Energy.

3
3. EXTERNAL VIEW
2. SPECIFICATIONS
* Specifications are subject to change without notice.
1. OUTER DIMENSION
MODEL KOC-154K9A27
POWER SUPPLY 120V~ 60Hz, SINGLE PHASE WITH EARTHING
MICROWAVE 1550W
POWER GRILL 1450W
CONSUMPTION CONVECTION 1750W
COMBINATION 1750W
MICROWAVE ENERGY OUTPUT 1000W
MICROWAVE FREQUENCY 2450MHz
OUTSIDE DIMENSIONS (W X H X D) 582X379.1X518.2mm (22.9x14.9x20.4 in.)
CAVITY DIMENSIONS (W X H X D) 390X285.5X383mm (15.4x11.2x15.1 in.)
NET WEIGHT Approx. 24Kg (52.9 lbs)
TIMER 60 minutes
FUNCTION SELECTIONS MICROWAVE/ GRILL/ CONVECTION/ COMBINATION
POWER SELECTIONS 10 LEVELS
CAVITY VOLUME 1.5 Cu. Ft

4
2. FEATURE DIAGRAM
1. DOOR HOOK
When the door is closed, it will automatically lock
shut. If door is opened while oven is operating, the
magnetron will immediately stop operating.
2. DOOR VIEWING SCREEN
Allows viewing of food. The screen is designed so
that light can pass through, but not the microwave.
3. DOOR SEAL
Door seal maintains the microwave energy within
the oven cavity and prevents microwave leakage.
4. CONVECTION OUTLET & FAN
5. TOP HEATER
Turns on when convection, grill and combi cooking
is selected.
6. UNDER HEATER
7. COUPLER
This fits over the shaft in the center of the ovens
cavity floor. This is to remain in the oven for all
cooking.
8. ROLLER GUIDE
This must always be used for cooking together with
the turntable tray.
9. METAL TURNTABLE TRAY
This is to be used for convection, combination and
grill cooking. It rotates during cooking.
10. GLASS TURNTABLE TRAY
This is to be used for microwave cooking. It rotates
during cooking.
11. METAL RACK (High)
12. METAL RACK (Low)
13. OVEN LAMP
Automatically turns on during oven operating.
14. SAFETY INTERLOCK SYSTEM
15. CONTROL PANEL

5
1. Steady, flat location
This microwave oven should be set on a steady, flat surface.
This microwave oven is designed for counter top use only.
2. Leave space behind and side
All air vents should be kept a clearance. If all vents are covered during operation, the oven may overheat and, eventually,
cause failure.
3. Away from Radio and TV sets
Poor television reception and radio interference may result if the oven is located close to a TV, Radio, antenna or feeder
and so on.
Position the oven as far from them as possible.
4. Away from heating appliances and water taps
Keep the oven away from hot air, steam or splash when choosing a place to position it, or the insulation might be
adversely affected and breakdowns occur.
5. Power supply
• Check your local power source. This microwave oven requires a current of approximately 13 amperes, 120V, 60Hz.
• Power supply cord is about 0.8 meters long.
1. A short power-supply cord is provided to reduce the risks resulting from becoming entangled in or tripping over a
longer cord.
2. Longer cord sets or extension cords are available and may be used if care is exercised in their use.
3. If a long cord or extension cord is used:
1) The marked electrical rating of the cord set or extension cord should be at least as great as the electrical rating of
the appliance.
2) The extension cord must be a grounding type 3-wire cord.
3) The longer cord should be arranged so that it will not drape over the counter top or tabletop where it can be pulled
on by children or tripped over unintentionally.
7. Examine the oven after unpacking for any damage such as:
A misaligned door, broken door or a dent in cavity.
If any of the above are visible, DO NOT INSTALL, and notify dealer immediately.
4. INSTALLATION

6
5. CONTROL PANEL
DISPLAY WINDOW
1. MICROWAVE - indicator, showing
microwaving in progress.
2. DEFROST - indicator, showing defrosting
in progress.
3. GRILL(upper grill heater) - indicator,
showing griling in progress.
4. GRILL(lower grill heater) - indicator,
showing griling in progress.
5. CONVECTION - indicator, showing
convectioning in progress.
6. CHILD LOCK - indicator.
7. % - percentage microwave power level
indicator.
BUTTONS
8. memory - Use to set favorite cooking
mode.
9. language - Press to select the language.
10. clock - Use to set clock.
11. crusty/cake - Press to select crusty/cake
menu.
12. auto cook - Press to select auto cook
menu.
13. auto defrost - Press to select defrost
menu.
14. grill - Use to select grill.
15. convection - Use to select convection.
16. m/w - Use to select microwave.
17. combi - Use to select combi.
18. Menu Knob - Use to select menus.
19. more - Use to add time to cooking.
20. less - Use to reduce cooking time.
21. Power/Temp/Mode - Use to set power,
temperature and grill/combi mode.
22. dial knob - Use to set time, weight and
quantity.
23. stop/clear - Press once to stop a
programme, and twice to cancel a
programme.
24. start/speedy cook - Press to start a
programme, also for speedy start (each
press adds 30 seconds to microwave
cooking time).

7
6. DISASSEMBLY AND ASSEMBLY
- Cautions to be observed when trouble shooting.
Unlike many other appliances, the microwave oven is high-voltage, high-current equipment.
It is completely safe during normal operation. However, carelessness in servicing the oven can result in an electric
shock or possible danger from a short circuit.
You are asked to observe the following precautions carefully.
1. Always remove the power plug from the outlet before servicing.
2. Use an insulated screwdriver and ware rubber gloves when servicing the high voltage side.
3. Discharge the high voltage capacitor before touching any oven
components or wiring.
(1) Check the earthed.
Do not operate on a two-wire extension cord.
The microwave oven is designed to be used with earthed.
It is imperative, therefore, to makes sure it is earthed properly
before beginning repair work.
(2) Warning about the electric charge in the high voltage capacitor.
For about 30 seconds after the operation stopped and electric
charge remains in the high voltage capacitor. When replacing or
checking parts, short between oven chassis and the negative
high terminal of the high voltage capacitor, by using a properly
insulated screwdriver to discharge.
4. When the 15A fuse is blown out due to the operation of the monitor
switch; replace primary interlock switch, secondary interlock switch
and interlock monitor switch.
5. After repair or replacement of parts, make sure that the screws are
properly tightened, and all electrical connections are tightened.
6. Do not operate without cabinet.
CAUTION : Service personnel should remove their watches whenever working close to or replacing the magnetron.
WARNING : When servicing the appliance, need a care of touching or replacing high potential parts because of
electrical shock or exposing microwave. These parts are as follows - HV Transformer, Magnetron,
HV Capacitor, HV Diode.

8
1. To remove cabinet
1) Remove 5 screws on the cabinet back and side.
2) Push the cabinet backward.
2. To remove door assembly
1) Remove two screws which secure the stopper hinge top.
2) Remove the door assembly from top plate of cavity.
3) Reverse the above for reassembly.
NOTE : After replacing the door assembly, perform a check of correct alignment with the hinge and cavity front plate.

9
3. To remove door parts.
A01 A02 A03 A04
A05A06A10A07A08A09
NO PARTS CODE PARTS NAME DESCRIPTION Q'TY REMARK
A01 3512210300 FRAME DOOR PC 1
A02 3515204900 STOPPER HINGE *T AS KOC-1B0K0S 1
A03 3511714110 DOOR SEAL AS KOC-154K8S 1
A04 3512302800 GASKET DOOR PBT 1
A05 3513101800 HOOK POM 1
A06 3515101800 SPRING HOOK PW1 1
A07 3517008920 BARRIER-SCREEN *O GLASS T3.2 TEMPERED 1
A08 3512607400 HANDLE AS KOC-154K8S 1
A09 3516006800 SPECIAL BADGE AL KOC-154K8S 1
A10 7122401211 SCREW TAPPING T2S TRS 4X12 2

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(1) Remove the gasket door from door plate.
(2) Remove two screws from the handle assembly secured to door frame.
(3) Remove the handle door and barrier screen outer from door frame.
(4) Remove the door frame from door plate.
(5) Remove the stopper hinge top from door plate.
(6) Remove the spring and the hook.
(7) Reverse the above steps for reassembly.
4. Method to reduce the gap between the door seal and the oven front surface.
(1) To reduce gap located on part ‘A’.
• Loosen two screws on stopper hinge top, and then push the door
to contact the door seal to oven front surface.
• Tighten two screws.
(2) To reduce gap located on part ‘B’.
• Loosen two screws on stopper hinge under, and then push the
door to contact the door seal to oven front surface.
• Tighten two screws.
NOTE : A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm
2
.

11
5. To remove control panel parts.
(1) Remove four screws(B14) which secure the control panel.
(2) Pull out the main PCB assembly(B13).
(3) Remove 11 screws(B12) which secure the control panel.
(4) Pull out the sub PCB assembly(B07).
(5) Pull out the knob function (B09) and the knob volume(B10) from the sub PCB assembly.
(6) Pull out the coupler vpc knob (B08) from the sub PCB assembly.
(7) Pull out three buttons from the control panel.
(8) Pull out decorator ring(B11) from the control panel.
(9) Pull out the decorator c-panel (B01) from the control panel.
(10) Reverse the above steps for reassembly.
NO PARTS CODE PARTS NAME DESCRIPTION Q'TY REMARK
B01 3511617310 DECORATOR C-PANEL SAN 1
B02 3511617300 DECORATOR C-PANEL STS TO.5 #4 1
B03 3516735410 CONTROL-PANEL ABS 1
B04 3516916000 BUTTON FUNCTI0N-A ABS 1
B05 3516916100 BUTTON FUNCTI0N-B ABS 1
B06 3516916200 BUTTON FUNCTI0N-C ABS 1
B07 PKBPMSF200 PCB BUTTON MANUAL AS KOC-154K8S 1
B08 3517401700 COUPLER VPC KNOB POM 1
B09 3513411400 KNOB FUNCTION ABS 1
B10 3513411500 KNOB VOLUME ABS 1
B11 3511617400 DECORATOR RING ABS 2
B12 7621301011 SCREW TAPPING T2S PAN 3X10 11
B13 PKMPMSF220 PCB MAIN MANUAL AS KOC-154K9A 1
B14 7122401211 SCREW TAPPING T2S TRS 4X12 4

12
CAUTION : Never install the magnetron without the metallic gasket plate which is packed with each magnetron to
prevent microwave leakage. Whenever repair work is carried out on magnetron, check the microwave
leakage. It shall not exceed 4mW/cm
2
for a fully assembled oven with door normally closed.
Magnetron antenna
Metallic
gasket
plate
Cooling fin
Filament
terminal
6. To remove high voltage capacitor.
(1) Remove a screw which secure the grounding ring
terminal of the H.V.diode and the capacitor holder.
(2) Remove the H.V. diode from the capacitor holder.
(3) Reverse the above steps for reassembly.
◆ High voltage circuit wiring
7. To remove magnetron.
(1) Remove a screw which secure the magnetron.
(2) Remove the magnetron.
(3) Reverse the above steps for reassembly.

13
9. To remove H.V.transformer.
(1) Remove four screws holding the H.V transformer.
(2) Remove the H.V.transformer.
(3) Reverse the above steps for reassembly.
8. To remove wind guide assembly.
(1) Remove a screw which secure the wind guide assembly.
(2) Draw forward the wind guide assembly.
(3) Pull the fan from the motor shaft.
(4) Remove two screws which secure the motor shaded pole.
(5) Remove the motor shaded pole.
(6) Reverse the above steps for reassembly.

14
10. To remove Guide air assembly parts.
1) Remove two screws (G06) and pull out Guide air assembly.
2) Remove a screws (G07) and pull out the lamp.
3) Remove two screws (G08) and pull out the two spring terminals.
4) Remove two screws (G09).
5) Pull out the motor and the bracket damper.
6) Reverse the above steps for reassembly.
NO PARTS CODE PARTS NAME DESCRIPTION Q'TY REMARK
G01 3512525200 GUIDE AIR PP GP-2300 1
G02 3513601500 LAMP BL 125V 25W 1
G03 3515102700 SPRING TERMINAL SUS301 T0.5 2
G04 3966820200 MOTOR SYNCRO 120V 2W GM-16-12F17 1
G05 3510609100 BRACKET DAMPER SBHG T0.7 1
G06 7112401011 SCREW TAPPING T1 TRS 4X10 2
G07 7112401011 SCREW TAPPING T1 TRS 4X10 1
G08 7121400611 SCREW TAPPING T2S PAN 4X6 2
G09 7121400611 SCREW TAPPING T2S PAN 4X6 2

15
11. To remove Top heater assembly parts.
1) Remove two screws (D01) and pull out Guide air outlet (D02) and insulator heater *t (D03).
2) Pull out the Top heater assembly.
3) Pull out the Harness heater (D08).
4) Remove a screw (D09).
5) Pull out the Braket heater*t(D07) from the Cover heater*t(D04).
6) Pull out the Heater miraclon(D06) from the Cover heater*t(D04).
7) Remove two screws (D10).
8) Remove reflector heater *t (D05).
9) Reverse the above steps for reassembly.
REF NO. PART CODE PART NAME DESCRIPTION Q’TY REMARK
D01 7112401011 SCREW TAPPING T1 TRS 4X10 2
D02 3512523600 GUIDE AIR OUTLET SBHG T0.5 1
D03 3513304000 INSULATOR HEATER *T SECC TO.5 1
D04 3511407600 COVER HEATER *T STS430 T0.4 1
D05 3512806010 REFLECTOR HEATER *T SUS 1
D06 3512803820 HEATER MIRACLON 60V 550W 2
D07 3510607700 BRACKET HEATER *T SA1D-80 T0.5 1
D08 3512767000 HARNESS HEATER KOC-1B0K0S 1
D09 7S432X4081 SPECIAL SCREW TT3 TRS 4X8 SE MFZN 1
D10 7122408114 SCREW TAPPING T2S TRS 4X6 MFNI 2

16
12. To remove Rear heater assembly parts.
REF NO. PART CODE PART NAME DESCRIPTION Q’TY REMARK
F01 3511413500 COVER *B SBHG-3 TO.4 1
F02 3512806400 HEATER 120V 1400W 1
F03 7112401011 SCREW TAPPING T1 TRS 4X10 2
F04 7112401011 SCREW TAPPING T1 TRS 4X10 1
C01 3513002300 HOLDER HEATER SUS304 T0.5 3
C02 3512801800 HEATER 230V 1400W 1R18344 1
C03 3511800700 FAN CONVECTION SA1D-80 T0.5 1
C04 3512806000 HEATER REFLECTOR SA1D T0.5 1
C05 3511409800 COVER HEATER *B SA1D-80 T0.5 1
C06 3513303400 INSULATOR HEATER *B SBHG-1 T0.5 1
C07 3963822620 MOTOR SHADED POLE 120V 60HZ MW10XA-T02 1
C08 7400104011 WASHER PLAIN PW-1-4 MFZN 1
C09 3511800900 FAN PBT 1
C10 7402704600 RING C CR-5 SK5 1
C11 3512781320 HARNESS CONVECTION AS KOC-154K9A 1
C12 7113400814 SCREW TAPPING T1 BIN 4X8 MFNI 1
C13 7001401065 SCREW MACHINE PAN 4X10 BSNI 2
C14 7S627W40X1 SPECIAL SCREW NUT FLANGE M4 1
C15 7113400814 SCREW TAPPING T1 BIN 4X8 MFNI 3
C16 7113400814 SCREW TAPPING T1 BIN 4X8 MFNI 4
C17 7601400811 SCREW MACHINE PAN 4X8 PW 2
1) Remove two screws (F03) and pull out Cover motor *B (F02).
2) Remove a screw (F04) and pull out Cover *B (F01).
3) Remove three screws (C12) (C13) and pull out the harness convection (C11).
4) Remove four screws (C16) and then pull out the Rear heater assembly.
5) Remove the C-Ring (C10) and then pull out the Fan (C09) from Motor shaft.
6) Remove a Nut (C14) and the pull out the Fan convection (C03) and Washer plain (C08).
7) Remove three screws (F15) and pull out the holder heater (C01) and the heater (C02).
9) Remo two screws (C17) and then separate the lnsulator heater *B (C06) and Motor shaded pole (C07).
10)Reverse the above steps for reassembly.

17
1) Cut the Motor syncro. Cover parts from the base plate.
2) Remove a screw and then pull out Motor syncro.
3) Remove a screw (E05) and then pull out the Under heater *U. assembly.
4) Remove a screw (E04).
5) Pull out the Heater *U (E01) from the Cover heater *U (E02).
6) Reverse the above steps for reassembly.
13. To remove Motor synchro. And Under heater assembly parts.
CUTTING (6EA)
E04
E02
E05
E01
E03
REF NO. PART CODE PART NAME DESCRIPTION Q’TY REMARK
E01 3512806300 HEATER *U 120V 300W 1
E02 3511407500 COVER HEATER *U STS430 T0.5 1
E03 3515304000 SUPPORTER HEATER *U STS430 T0.5 1
E04 7113400814 SCREW TAPPING T1 BIN 4X8 MFNI 1
E05 7113400814 SCREW TAPPING T1 BIN 4X8 MFNI 1

18
7. INTERLOCK MECHANISM AND ADJUSTMENT
The door lock mechanism is a device which has been specially designed to completely eliminate microwave radiation when
the door is opened during operation, and thus to perfectly prevent the danger resulting from the leakage of microwave.
(1) Primary interlock switch
When the door is closed, the hook locks the oven door. If the door is not closed properly, the oven will not operate.
When the door is closed, the hook pushes the lock lever downward. The lock lever presses the button of the
microswitch.
Then the button of the primary interlock switch bring it under “ON” condition.
(2) Secondary interlock switch and interlock monitor switch
When the door is closed, the hook pushes the lock lever downward. The lock lever presses the button of the interlock
monitor switch to bring it under “OFF” condition and presses the button of the secondary interlock switch to bring it under
“ON” condition.
(3) Adjustment steps
a) Loosen the one mounting screw.
b) Adjust interlock switch assembly position.
c) Make sure that lock lever moves smoothly after adjustment is completed.
d) Tighten completely one mounting screw.
ADJUSTMENT :
Interlock monitor switch
When the door is closed, the interlock monitor switch should be opened before other switches are closed.
When the door is opened, the interlock monitor switch should be closed after other switches are opened.
NOTE :
Microwave emission test should be performed after adjusting interlock mechanism.
If the microwave emission exceed 4mW/cm
2
, readjust interlock mechanism.

19
8. TROUBLESHOOTING GUIDE
Following the procedure below to check if the oven is defective or not.
1) Check grounding before trouble checking.
2) Be careful of the high voltage circuit.
3) Discharge the high voltage capacitor.
4) When checking the continuity of the switches, fuse or high voltage tranformer, disconnect one load wire from these
parts and check continuity with the AC plug removed. To do otherwise may result in a false reading or damage to
your meter.
NOTE : When electric parts are checked, be sure the power cord is not inserted the wall outlet.
Check wire harness, wiring and connection of the terminals and power cord before check the parts listed below.
CONDITION CHECK
Check continuity of
interlock monitor switch with
door closed
(COM↔NC)
Check continuity of
both primary and secondary
interlock switch with door closed
Malfunction of
Interlock
monitor switch
Malfunction of
interlock switch
RESULT
Continuity
No continuity
CAUSE REMEDY
Replace
(COM↔NC)
Fuse blows.
Replace
Shorted contacts
of primary
interlock Switch
Continuity Replace
Check continuity of
primary interlock switch contact with
door partially open until interlock
monitor switch contact close
( COM↔NC close )
Defective low
voltage
transformer
Defective
high voltage
transformer
0 Ωor infinite Replace
Replace
Check continuity of
primary winding of low voltage
transformer
Disconnect high voltage
fuse and operate the unit
No
Continuity
Continuity
Approx.
530Ω
( normal )
Fuse again
blows