BASIC PARTS OF A TOASTER OVEN AND ITS FUNCTION
Learning Objectives;
a. identify the parts of a oven toaster
b. explain each part of the oven toaster
Introduction:
Toaster is an electrical or a typical small kitchen appliance used to toast a
bread. Bread that is cut into slices and cooked at a high temperature to make it
brown and crisp is referred as toast. Although, there are also toasters that are not
electrically operated, instead, a fire or flame is used to toast bread products. This
lesson will focus on electric toaster oven that is common nowadays in our kitchen.
The toaster ovens at present are not just for toasting breads, instead the function
was extended to other related tasks for particular purpose. The additional task are
baking, roasting and broiling.
There are lots of available toasters in the market to choose from.
The three selections among toasters are pop-up toaster, toaster oven, and
conveyor toaster. Toaster oven will be the focus of this lesson. Toaster oven is a
small electric oven with front door, wire holder and a removable pan for roasting.
This domestic appliance is considered as a miniature oven that allows you to bake
and broil foods. Combination of heating elements is used to provide desired
temperature for the purpose. As the unit is plugged-in to the power source, set of
controls are turned to the desired level allowing the current to flow throughout the
circuit. The heating element is energized and therefore produces equivalent
temperature suited for the purpose. Timer switch sets how long the cooking takes
and turns the unit off upon cycle completes. Several functions were incorporated to
toaster oven nowadays resulting to additional control.
Toaster oven may vary its capabilities and features depending on the brand,
model, and application. The following procedures could be used as reference.
Toast function
This is used for toasting breads and other similar foods. All heating elements
are used during this function.
1. Place the oven rack on the middle oven rails.
2. Turn the TEMP control knob to 450°F.
3. Turn the FUNCTION control knob to TOAST.
4. Place the food to be toasted on the oven rack.
5. Turn the TIME control knob to the required browning level. The POWER
indicator turns on. (See owner’s manual for preferred setting)
6. At the end of the toasting cycle, a bell will ring, to indicate the cycle has finished,
and the appliance switches off. The POWER indicator turns off
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
Page 1
LO. NO.1 PREPARE TO ASSEMBLE Revision # 01
ELECTRONIC PRODUCTS
BAKE FUNCTION
This function provides constant and even heat suitable to be used for baking
(cookies, cakes, and pies), and roasting (beef, pork, chicken, or other meat). All
heating elements are used during this function. The convection fan circulates the
hot air around the inside of the appliance.
1. Place the broil rackin the appliance.
2. Turn the TEMP control knob to the required temperature.
3. Turn the FUNCTION control knob to BAKE.
4. Preheat the appliance, if required, by turning the TIME control knobto the
required time. The POWER indicator turns on
5. Place the baking dish with the item/s to be baked on the broil rack.
6. Turn the TIME control knob to STAY ON or to the required time. The POWER
indicator turns on.
7. If a time was set, a bell will ring at the end of the cycle, to indicate the cycle has
finished, and the appliance switches off (POWER indicator turns off).
8. If no time was set, turn the TIME control knob to OFF when baking is
completed. The POWER indicator turns off.
Roast function The procedures given in the Bake function are the same. It
is recommended to refer to the instruction manual of your appliance.
Rotisserie function Do not to use a roast larger than 5lb. on the spit. Only
the upper heating elements are used during this function. Chicken should be
bound to prevent the legs or wings from separating during roasting and to allow the
rotisserie assembly to rotate smoothly. It is recommended to use a meat
thermometer to check the roasting progress.
The procedures given in the Bake function are the same. It is recommended
to refer to the instruction manual of your appliance.
Keep warm function
After 30 minutes, food may become dry and starts to spoil.
1. Place the broil rack on the oven rails in the middle of the appliance.
2. Turn the TEMP control knob to 180°F.
3. Turn the FUNCTION control knob to WARM.
4. Place the cooked food on the broil rack.
5. Turn the TIME control knob to STAY ON or as to required time. The
POWER indicator turns on.
6. If the time was set, a bell will ring at the end of the cycle and the POWER
indicator turns off.
7. Remove the food from the appliance, and then switch the appliance to off
position by turning the TIME control knob to OFF. The POWER indicator
turns off.
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
Page 2
LO. NO.1 PREPARE TO ASSEMBLE Revision # 01
ELECTRONIC PRODUCTS
CAUTION: Always wear oven mittens when placing or removing items from the
appliance. Use caution when sliding the broil rack in and out of the appliance.
A) Parts of a Toaster Oven (Manually Operated)
Parts and components may vary due to brand, model and feature/s of toaster oven
available. The following numbered parts are identified and its function defined on
the next page
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
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LO. NO.1 PREPARE TO ASSEMBLE Revision # 01
ELECTRONIC PRODUCTS
Parts FUNCTIONS
A small round object or lever that is attached to the glass door and
1. Door Handle
used for opening and closing it
Used to secure the food and temperature inside the toaster oven. A
2. Glass Door
glass is used for viewing of food.
Lower Door
3. Part of the housing where the door hinges are fixed.
Frame
Temperature A turning knob used to adjust the thermostat to the desired
4. Control Knob temperature.
Power
5. To indicate that the toaster oven in ON.
Indicator
Function
6. A turning knob used to set the cooking function to a desired setting
Control Knob
A turning knob used to set the cooking time up to certain minutes
7. Timer Knob
and will turn the oven OFF at the end.
8. Power Cord Used to connect the appliance to the power source
9. Housing A compartment where all parts of the toaster oven in place.
This is used for toasting, baking, and general cooking with casseroles
10. Griddle
and other cookware.
Used for all you’re baking and roasting needs, attaches to Oven/Broil
11. Griddle Cover
Rack.
Griddle Cover A small object or lever that is attached to the cover for holding
12. Handle purpose..
Wire/ Broil/ This is used for toasting, baking, and general cooking with casseroles
13. Cooking Rack and other cookware
Bake/ Used for all you’re baking and roasting needs, attaches to Oven/Broil
14 Roasting Pan Rack.
15. Crumb Tray A removable part inside the bottom of the oven.
Rotisserie
16. Removal Used to safely remove/ replace the rotisserie
Handle
17. Tray Handle Used to safely remove/ replace the tray.
Rotisserie
18. Used in roasting purpose.
Skewer
19. Drive mount The interface for the skewer
This is activated to provide air circulation around the food for faster
20 Convection fan
and more even cooking.
Two Rack
21. To accommodate a variety of foods.
Levels
Upper heating
22. Provide required temperature from the top.
elements (x2)
Lower heating
23. Provide required temperature from the bottom
elements (x2
24. Pizza pan For broiling and baking pizza.
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
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PARTS NAME
1 Control Panel 9. Set 17 Temperature
. .
2 LCD Screen 10 Door Frame 18 Convection
. . .
3 PowerPlus™ Convection 11 Flat Glass Door 19 Cook Time
. . .
4 Function/Mode Control 12 Door Handle 20 Pizza Pan
. . .
5 Start/Cancel 13 Toast/Bagel 21 Cooking Rack
. . .
6 Temp/Darkness 14 Number of Slices 22 Bake Pan
. . .
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
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LO. NO.1 PREPARE TO ASSEMBLE Revision # 01
ELECTRONIC PRODUCTS
7 Time/Slices/Size 15 Preheat Icon 23 Crumb Tray
. . .
8 Temp/Timer 16 Pizza Size
. .
SAFETY REMINDERSIN USING A TOASTER OVEN
1. Read carefully the instructions in the user’s/ operation/ owner’s manual before
using a toaster oven. 2. Do not touch hot surfaces. Handles and knobs are provided
for the user to easily open/close the glass door and to turn right or left the
controls. Auxiliary parts are included in the package for holding purposes.
3. Keep away the cord, plugs, or appliance from the water or other liquid to avoid
electric shock.
4. Unplug the toaster from outlet (power source) when not in use.
5. Do not use any appliance with a damaged cord or plug.
6. Before cleaning, unplug the cord and let the unit cool down prior to taking off
parts for cleaning.
7. Place the appliance in stable position.
8. Do not use metal scouring pads in cleaning a toaster oven. This can damage the
pad (buttons) and might cause electrical hazard.
9. Use only accessory that is recommended by the manufacturer to avoid injuries.
10. Keep at least four inches of space on all sides of the toaster oven to allow
adequate air circulation during operation.
11. In case the plug is detachable from the unit, attach the plug to appliance first
and then plug cord into the wall outlet. To unplug, turn the control to OFF first,
and then remove the cord by grasping and pulling out the plug. Never pull the cord.
12. Do not use metal foil to cover Crumb Tray or any part of the toaster oven to
avoid overheating.
13. When removing tray or disposing of hot grease or other hot liquids extreme
caution must be observed.
14. Do not place unnecessary item on top of the oven during operation. The unit
must be far from flammable materials (curtain, walls and the like).
15. Always wear protective, insulated oven mitts when putting in or removing items
from the hot toaster oven.
16. Avoid scratching the glass door surface.
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
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17. If the appliance malfunctions or has been damaged, seek technical assistance
from servicemen for inspection, repair, or adjustment
Sample diagram of a toaster oven (w/grilling and baking function)
Mechanical
Technical Specifications
Timer Mechanical (max. 20 min.
Thermostat Adjustable (300C to 2550C)
Grill motor 2 r.p.m.
Elements top R1= 650 W
R2= 500 W
Elements bottom R3 = 700 W
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
Page 7
LO. NO.1 PREPARE TO ASSEMBLE Revision # 01
ELECTRONIC PRODUCTS
Position Elements switched ON Max. power consumption
Function
1. Grilling R1 + R2 1150 W
2. Baking R1 + R3 1350 W
3. toasting R3 700 W
PRE-TESTING and TROUBLESHOOTING A TOASTER OVEN
(ELECTRONICALLY-CONTROLLED)
Learning Objectives:
At the end of these INFORMATION SHEET, YOU MUST be able to
a. identifies the defective parts of the oven toaster
b. Troubleshoot the problem of the appliances.
Introduction:
1. Determine the specific problem by asking the symptom.
a) Ask the owner/operator of the toaster oven of what is the symptom of the
unit.
b) Request some details of the symptom (how does the symptom happen and
how long it has been observed).
2. Operate the device if possible. Make sure that you know how to operate a toaster
oven. If not, review the operating manual as well as service manual (if available) of
the unit prior to its testing and operation.
a. If you have worked on the same unit before, check out to see if it
functions in the same way.
b. Determine the last time it has been modified/repaired.
c. You must recognize the symptom/ complain of the owner to the unit.
3. Perform visual inspection of the unit.
a. Prepare the tools needed and remove the cover ready for inspection.
b. Apply careful physical inspection of the parts/components. (Look for
burned and broken components; Inspect for loose connections or broken
wires; Check for misaligned/ deformed parts)
4. If all looks fine, test the unit for resistance checks.
a. Get the multitester and set at lower range. Connect the test probes to
each of the plug terminals, the reading must be infinite having the
control/s at zero position.
b. Then, adjust slowly the timer, temperature, and function knob, decrease
in resistance should be observed upon turning the knob to the right. If
this happens, the unit might be in good condition. For safety, place one
probe across the plug terminals and the other probe to the body. There
should be very high (infinite) resistance. If resistance is observed, do not
attempt to plug the unit instead solve this first. Refer to troubleshooting
guide in this lesson
5. Record your findings for future reference.
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
Page 8
LO. NO.1 PREPARE TO ASSEMBLE Revision # 01
ELECTRONIC PRODUCTS
Diagnosing and Troubleshooting Procedure/ Guide SYMPTOM: Toaster
oven is not working.
POSSIBLE DEFECT PROCEDURE CORRECTIVE MEASURE
Power cord Check the continuity of Replace power cord if
the power cord using necessary.
ohmmeter
Power source Check the power at the Insert the power plug into
outlet a different outlet. Reset
the circuit breaker if
necessary.
Fuse Check the continuity of Replace fuse if necessary
the fuse using ohmmeter
SYMPTOM: Toaster oven is energized but not reach set temperature
POSSIBLE DEFECT PROCEDURE CORRECTIVE
MEASURE
Door not closed Check the door Ensure the door is
closed properly
Compare the thermostat Replace the thermostat
setting and temperature if necessary.
SYMPTOM: Food not fully cooked
POSSIBLE DEFECT PROCEDURE CORRECTIVE MEASURE
Setting too low Check the function Set the function setting
setting as to as to requirements
requirements
Check the temperature Set the temperature
setting as to setting as to
requirements requirements
Check the timer setting Set the timer setting as to
as to requirements requirements
SYMPTOM: Food over cooked or bunt
POSSIBLE DEFECT PROCEDURE CORRECTIVE MEASURE
Setting too high Check the function Set the function setting
setting as to as to requirements
requirements
Check the temperature Set the temperature
setting as to setting as to
requirements requirements
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
Page 9
LO. NO.1 PREPARE TO ASSEMBLE Revision # 01
ELECTRONIC PRODUCTS
Check the timer setting Set the timer setting as to
as to requirements requirements
SYMPTOM: The skewer is not rotating
POSSIBLE DEFECT PROCEDURE CORRECTIVE MEASURE
Oversize food Check the food on the Switch off the appliance
skew for its size and and remove the skew to
part/s touching the reduce size of food.
housing. Return the skew and
continue the process
SYMPTOM: The skewer is not rotating
POSSIBLE DEFECT PROCEDURE CORRECTIVE
MEASURE
Standby mode Backlight Press any button to Press any button to
LED activate the screen and activate the screen and
backlight. Nothing to backlight. Nothing to
correct. correct.
Check the temperature Check the temperature
setting as to requirements. setting as to
If the screen display is ok, requirements. If the
check the LED and replace screen display is ok,
if needed check the LED and
replace if needed
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
Page 10
LO. NO.1 PREPARE TO ASSEMBLE Revision # 01
ELECTRONIC PRODUCTS
Maintain and Repair of Oven Tester
Learning Objectives:
At the end of these INFORMATION SHEET, YOU MUST be able to
a. Troubleshoot the damage component of the Oven Toaster
b. Repair the damage component of the Oven Toaster
Introduction
Everyone knows that maintenance is important for product longevity and
performance Ovens for testing, laboratory and process applications are no
exception. Whether an oven is used in a tension test or an annealing
application, every oven owner needs a checklist to help keep the oven at peak
condition. And, ovens that have mounting assemblies or special cooling have
even more maintenance issues.
1. Conduct a quick diagnosis of the trouble symptom and repair the defective
set in the shortest possible time. Do not troubleshoot a toaster oven unless you
have determined the fault. Trace the fault from the mechanical section or
electrical circuit section.
2. When troubleshooting integrated circuits (ICs) in the electrical/electronic
circuit section, do not remove the IC from the PCB. Secure a circuit diagram
from the manufacturer to help you identify and analyze the function of the IC.
Consider the pin out of the IC.
3. When troubleshooting in the electrical/ electronic circuit section, prior to
pre-testing, consider voltage measurement on components first before removing
it for testing. If the measured voltage is normal, the component might be the
cause of the problem. Either way, if the measured voltage is not normal
(increased or decreased) the preceding circuit/ components might be the cause.
4. If the trouble symptom is caused by aging components, the defective
component is usually one of them. However, in high-power-handling circuits, a
defective component may cause other components to malfunction.
5. Be familiar with the usual defects of components. (e.g. capacitors usually
become leaky, shorted or open/ resistor increase their resistance when they
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
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LO. NO.1 PREPARE TO ASSEMBLE Revision # 01
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become defective/ semi-conductors such as transistors usually become open or
shorted)
6. Don’t replace an opened fuse or burned resistor unless you have corrected
the trouble.
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
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7. Check the mechanical switch circuit for its faulty contact before assuming
defective electronic components.
8. When measuring resistance in the circuit, make sure that the circuit if OFF
and power is not being supplied in the circuit, and that stored charges in
capacitors are properly discharged. Failure to do so can damage the volt-ohm-
milliameter (VOM) and the circuit due to the low resistance of the ohmmeter.
9. While using a VOM for in-circuit resistance measurement, always exchange
the setting of positive and negative probes. Take the higher meter reading with
the approximate resistance.
10. Use soldering irons with the proper power rating to prevent the components
and the circuit board from being overheated and damaged. Soldering iron tips
should be cleaned and preferably slim.
11. Use proper tools and soldering aids when troubleshooting PCB. Ground the
soldering iron to avoid damaging ICs and transistors.
12. Dry solder joints are hard to detect. However, when they are found or
suspected, remove the components from the PCB; then, file or clean the leads
and solder the joints back. Reheating dry joints with a new soldering lead is
another remedy. When re-soldering, make sure you do not overheat the
components. Overheating the PCB may cause the copper layer on it to warp and
peel off.
13. Use Personal Protective Equipment.
Maintenance of Toaster oven
1. Turn off the toaster oven and remove the cord from the source of voltage.
2. Apply lubricant to mechanical parts of the toaster oven that requires
lubrication through a drop of oil or grease to assure smooth operation without
grinding or squeaks.
3. Clean and check cooling louvers for any obstructions to avoid cutting off the
air flow.
4. Clean or wipe dust and foreign particles at the PC Board and metal parts of
the motor.
5. Replace worn or frayed AC cord and electrical wires.
Cleaning Instructions
1. After every use, it is important to clean all parts of the oven. This will prolong
the life of your appliance. 1. Always switch off, unplug and allow getting cool
before cleaning. Never use harsh abrasives or corrosive products. These could
damage the oven surface.
2. Use damp cloth to wipe the exterior of the toaster oven. Dry immediately. Do
not immerse in water.
3. Wipe the interior walls with a damp cloth and a mild liquid soap solution on
a sponge. Dry immediately.
4. Slide out the crumb tray and discard to remove. Wipe clean and return.
Procedure in Repairing a Toaster Oven
1. Once the specific electrical/mechanical problem is located:
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
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• consider the techniques for the proper removal of the defective component
or
parts;
• anticipate what to do if the replacement part does not correct the problem;
• and check the installation of the replacement or original part for any
improper
mounting in the mechanical assembly or circuit board.
2. Examine carefully the mounting of the replacement of original parts of the
system.
• Check the placement of the wires or leads of the replacement component.
• Consider significant factors used in the original installation such as
insulating
toaster oven, silicon grease and locating mark for pin connections.
• Observe proper placement of the component leads for electrical parts.
3. Perform the techniques for the proper soldering of electrical parts.
• Be careful not to damage adjacent components.
• Be careful not to lift the copper conductive path from circuit board base
material.
• Avoid any solder bridges between board paths.
• Do not destroy the component being removed in case it is still functional
and
be careful not to damage the component being installed.
4. Verify all connections and harness.
• Be sure that all components pre-positioned in a manner that will avoid the
possibility of having adjacent components short circuited.
• Be sure to check or inspect all insulators and barriers between sections
after
working on any model/brand of toaster oven.
• Check for frayed or broken insulation on all wiring including the AC line
cord.
• Be sure to replace fuses, resistors and capacitors with special designation
such
as flame proof to components equal to the original value for both safety and
liability purposes.
5. Once the repair is completed, perform an AC leakage test on all exposed
metal
parts of a toaster oven to eliminate the possibility of electric shock.
• Perform complete retesting of the toaster oven to ensure the correctness of
the
actual repair.
• Connect the toaster oven into the 60Hz power to allow the time period
required
to let the new parts settle in and operate as they are designed to work with
each
other.
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
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• Recheck or inspect if the repair was done correctly and the unit functions
properly to ensure successful completion of the repair.
6. Clean the toaster oven before it would be returned to the customer.
• Be sure that the front and rear guards of the toaster oven are properly
cleaned.
Be sure that proper cleaning is given to the control panel or switch box of
the
toaster oven
REASSEMBLING and TESTING REPAIRED TOASTER OVEN
Learning Objectives:
At the end of these INFROMATION SHEET, YOU MUST be able to:
a. Repair and replace the defective parts of the toaster oven
b. Re assemble the appliance according to procedure
Introduction:
Reassembling Procedure:
1. After replacing the defective component of the appliance, prepare the parts
for reassembling. Make sure that there are no missing part/ component and as
well as the screw/s.
2. Fix all the disassembled parts in the housing/ compartment, considering the
fittings/ lock/s
3. Wires and loose parts should be in proper place to avoid damaged due to
misaligned compartment.
4. All sides of the housing should fit accordingly. Moving parts must move as it
can be moved by hand and free from obstructions.
5. Tighten the screw/s accordingly.
6. Clean the unit before doing the post-testing procedure.
Post-testing Procedure:
1. Test the resistance at the AC plug to determine the continuity of the power
line to the heating element. A resistance reading must be observed as you turn
the timer switch to ON position. This indicates that the circuit connection is
good.
2. In the case of electronically-controlled toaster oven, there is no resistance
reading as you test the AC plug. The reason is that there is a low voltage power
supply circuit that controls the functions of the appliance.
3. Energize the unit to check its functionality. Plug the AC cord to the power
source (the timer switch is at OFF position and power ON button for
electronically-controlled must be OFF too). Turn the timer switch accordingly
and observe if the unit functions as it should be. In the case of electronically-
controlled, press button one at a time observing the behavior. This time, the
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
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unit should operate normally. If not, review the documentation and the problem
for the second time
Date Developed: Document No. EPAS-2020
Electronic Product Assembling and September 2020
Servicing NC II Issued by:
Date Revised:
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