Order No. PHAT070510C3
Service Manual
Automatic Rice Cooker
SR-GA421/SR-GA281/SR-GA721
EXPORT
COOK
WARM
SR-928
Rice Cooking
Keep Warm
SR-GA421/SR-GA281
SR-GA721
Specification
Model
SR-GA421
Detail
Country
Power Source
Power
consumption
Cooking
SR-GA281
HK
SIN-DBD
SIN-RBD
MALAYSIA
HK
MALAYSIA
SIN-DBD
SIN-RBD
USA
220 V / 50 Hz
230 V / 50 Hz
220 V / 50 Hz
240 V / 50 Hz
220 V / 50 Hz
240 V / 50 Hz
230 V / 50 Hz
220 V / 50 Hz
208 V / 50 Hz
1400 W
950 W
5 ~ 23 L
5 ~ 15 L
Center thermostat
working temperature
More than equal to 80 °C (After 1 Hr. keep warm)
Thermal fuse specification
Weight
169 °C
113
429 x 369 x 300
367
x 295
x 305
248 x 247 x 255
5.5 kg
3.6 kg
10.1 kg
Power Cord (approx.)
Accessories
3~7L
140 °C
Keep warm temperature
Dimension (mm)
Width x Depth x Height
2500 W
47.5 W
Warming
Cooking capacity
SR-GA721
1.0 m
Measuring cup, Steaming basket
Specification subject to change without notice.
Rice scoop
© 2007 Panasonic Home Appliance (Thailand) Co.,Ltd
All rights reserved. Unauthorized copying and distrbution
is a violation of law.
SR-GA421/SR-GA281/SR-GA721
CONTENTS
Page
1.SCHEMATIC DIAGRAM & WIRING DIAGRAM .....................................................................3-4
2.FUNCTION OF CENTER THERMOSTAT AND THERMAL FUSE .........................................5-6
3.TROUBLE SHOOTING GUIDE...............................................................................................7-8
4.TESTING PROCEDURE .........................................................................................................9-10
5.EXPLODED VIEW & PACKING VIEW (SR-GA421/SR-GA281) ............................................11-12
6.REPLACEMENT OF PARTS LIST & PACKING LIST (SR-GA421/SR-GA281) ....................13-14
7.EXPLODED VIEW & PACKING VIEW (SR-GA721) ..............................................................15-16
8.REPLACEMENT OF PARTS LIST & PACKING LIST (SR-GA721) .......................................17-18
WARNING
This service information is designed for experienced repair technicians only and is not designed for use by the general public.
It does not contain warnings or cautions to advise non-technical individuals of potential dangers in attempting to service a product.
Products powered by electricity should be serviced or repaired only by experienced professional technicians. Any attempt to service or
repair the product or products dealt with in this service information by anyone else could result in serious injury or death.
IMPORTANT SAFETY NOTICE
in the Schematic
There are special components used in this equipment which are important for safety. These parts are marked by
Diagrams, Circuit Board Diagrams, Exploded Views and Replacement Parts List. It is essential that these critical parts should
be replaced with manufacturer’s specified parts to prevent shock, fire or other hazards. Do not modify the original design without
permission of manufacturer.
2
SR-GA421/SR-GA281/SR-GA721
1. SCHEMATIC DIAGRAM & WIRING DIAGRAM
SCHEMATIC DIAGRAM (SR-GA421)
WIRING DIAGRAM (SR-GA421)
CAST HEATER
T.F.
(BIG)
N
(SMALL)
LAMP RESIST.
RICE COOKING NEON LAMP
E
LAMP RESIST.
INPUT
Green
KEEP WARM NEON LAMP
SWITCH
Silicone Tube (Blue)
10˚
±5
˚
Cord Bush
L
MICA HEATER ASS’Y
N
Silicone Tube (Brown)
Cord Wire Earth (Green)
Silicone Tube (Green)
Twist two time
Switch Lead Wire (Blue)
Lever Earth Lead Wire (Green)
Thermal Fuse Wire (Brown)
Lamp Lead Wire C (Brown)
Thermal Fuse Wire (Gray)
Lead Wire (Orange)
Lamp Lead Wire B (Gray)
Twist one time
Lamp Lead Wire A (Orange)
SCHEMATIC DIAGRAM (SR-GA281)
WIRING DIAGRAM (SR-GA281)
After ass’y, Mica Heater Ass’y must not overlie
the Outer Case of Center Thermostat.
T.F.
T.F.
Gray
Cast Heater
Blue
N
Glass tape 20 x 20 mm.
Rice Cooking Neon Lamp
E
Input
Green
After ass’y, gap between terminal and mica heater case must be more than 4 mm.
Lamp Resistor
Lamp Resistor
Keep Warm Neon Lamp
Switch
L
Brown
10˚ ±
5
Silicone Tube (Brown)
Silicone Tube (Blue)
Cord Bush
˚
Water guard
After assembly Mica Heater case
Must no touch the terminal of cast heat.
Mica Heater Ass’y
N
Cord Wire Earth (Green)
Silicone Tube (Green)
Lamp Lead Wire B (Gray)
Thermal Fuse Wire (Gray)
Thermal Fuse Wire (Blue)
Lamp Lead Wire C (Brown)
Twist one time
Lever Earth Lead Wire (Spiral Green)
Lamp Lead Wire A (Red)
Wiring Lead Wire (Brown)
3
SR-GA421/SR-GA281/SR-GA721
1. SCHEMATIC DIAGRAM & WIRING DIAGRAM
SCHEMATIC DIAGRAM (SR-GA721)
N
CAST HEATER
Blue
(SMALL)
T.F.2 T.F.1
(MIDDLE)
(BIG)
LAMP RESIST.
E
INPUT
Green
RICE COOKING NEON LAMP
LAMP RESIST.
KEEP WARM NEON LAMP
SWITCH
L
Brown
MICA HEATER ASS’Y
WIRING DIAGRAM (SR-GA721)
Cord Wire Earth (Green)
10˚
±5
˚
Keep warm lamp lead (Red)
Cathode lead wire (Brown)
Red
Brown
Grey
Cord Wire Blue (N)
Cord Wire Brown (L)
Heater lead wire A (Red)
Heater lead wire B (grey)
Thermal fuse lead wire (Blue)
Heater lead wire C (Brown)
User position
Thermal fuse lead wire (Grey)
4
SR-GA421/SR-GA281/SR-GA721
2. FUNCTION OF CENTER THERMOSTAT AND THERMALFUSE
A. Center Thermostat
The center thermostat senses when the bottom of the rice cooker pan reach 134°C ± 6°C.
And it’s action turns off the cooking cycle, and starts the warming cycle.
Center thermostat construction
Metal
Magnet
Figure 1
Cook switch button
Inner spring
Cooking heater
Rod
Outer
spring
Inner spring
(Cooking Position)
Switch lever
(Warming or Off Position)
NC
C
Micro switch
Refer to these figures showing the center thermostat construction and cooking position. As
the metal is heated, its ability to be attracted by the magnet decreases.
Finally, the inner spring pressure becomes stronger than the magnetic pull and the metal
and magnet will pop apart. The rod activates the switch lever which causes the auxiliary lever to
press the micro-switch button into the warming cycle.
B. Switch-On Preventive System
Thermostat surface
Inner spring
Outer spring
Thermostat case
Metal
Cooking heater
Magnet
10mm
Rod
Cook switch button
Auxiliary lever
Micro switch
Switch lever
This is design to prevent the rice cooker from being turned on without the pan placed into
position.
1) Normally when the pan is inserted properly into the rice cooker, the pan will depress the
center thermostat. The center thermostat outer spring will be compressed. In this case when
the switch button is depressed, the following will happen:
a. The auxiliary lever will release the micro-switch button. This puts the micro-switch in the
cook position.
b. The switch lever will push the rod which will allow the magnet to meet with the metal.
c. When the rice is cooked and the proper temperature has been reached 134°C ± 6°C, the
metal and magnet will pop apart as described in the center thermostat operation above.
d. The rod will push the switch lever and cause the auxiliary lever to depress the microswitch button. This puts the micro-switch in the warming position.
2) When the pan is not in place within the rice cooker, the center thermostat is not depressed.
a. In this condition, the outer spring is not compressed within the center thermostat
preventing the metal from reaching its normal operating position.
b. When the switch button is depressed, the switch lever and auxiliary lever work as above
but the magnet cannot come in contact with the metal to hold the switch lever in the cook
position. This happens because the switch lever hits the thermostat case and cannot push
the rod, with the magnet attached, all they way up to meet with the metal.
c. When the pressure is taken off the switch button, the switch lever releases immediately to
the open or warm positions.
5
SR-GA421/SR-GA281/SR-GA721
2. FUNCTION OF CENTER THERMOSTAT AND THERMALFUSE
C. Thermal Fuse
The thermal fuse is used to open the circuit to the cooking heater when the temperature has
gone unusually high. This happens in cases such as incomplete contact between the heater
and pan or if the switch buttons is forced to stay on keeping the heater energized abnormally.
This fuse is not a resetting device and must be replaced after openning.
Whenever replacing the fuse make sure the protective cover is placed over all exposed wiring.
Cause of Fusion
[A] Improper contract between heater and pan
Remedy
Cause
Pan collar or deformed
Foreign matter adhering
Body dented or deformed
Pan bottom dented or
deformed
Heater surface deformed
or corroded
Remove foreign matter
by of (-) screw-driver,
etc., and then polish with
= 320 water paper while
wetting it with water.
Repair or replace body.
Replace pan.
Replace cooking heater.
Remedy
Cause
[B] Forced application of current
Chopstick, wooden
piece, etc. inserted onto
cooking button. (continuous application of current)
Switch lever deformed
or maladjusted, causing
continuous application of
current.
Inserted to prevent earlier turning off? Refer to
cause in (a) above.
Repair or replace parts.
When fusion takes place, check the cause, set right the faulty section, and be sure to use
replacement parts.
6
SR-GA421/SR-GA281/SR-GA721
3. TROUBLESHOOTING GUIDE
When receiving the cooker to be repaired, be sure to always take charge of not only the
cooker body but also the pan and the lid, and ask for details as to the symptom of the trouble.
Furthermore, when making troubleshooting of each part, be sure to remove the power plug from
the socket.
Symptom
Cooking function
● Cooking fails (Cooking
lamp is not shown)
Diagnosis
No continuity of cord?
No
Remedy
Yes
● Replace AC cord.
Yes
● Locate cause for fusing and
replace fuse.
No continuity of thermal fuse?
No
Yes
No continuity of micro switch?
No
● Replace Frame ass’y.
Yes
Center thermostat is broken?
(Checked evaporation test)
● Replace center thermostat.
No
No
Switch lever properly adjust?
● Cooking fails (Cooking
lamp is not shown)
● Adjust Switch lever.
Yes
No continuity of sheathed heater?
● Thermal fuse blown
● Replace sheathed heater.
Yes
Forced application of current?
● Rice burns (Brown color)
Center thermostat defective?
(Check with evaporation test)
No
● Explain correct usage.
Yes
● Replace center thermostat.
No
Switch lever has been properly adjusted?
● Adjust Lever.
Yes
Usage correct?
● Rice is not rinced well enough?
● Using with low rated voltage?
● Too much water input for cooking?
7
Yes
● Explain correct usage.
SR-GA421/SR-GA281/SR-GA721
3. TROUBLESHOOTING GUIDE
Symptom
● Earlier Switching-off
● Poor cooking finish
Too hard
Too soft
Half-boiled
Diagnosis
Remedy
Yes
Poor contact between pan and sheathed
heater? (Check with bubbling test)
No
● Replace pan or sheathed
heater.
Yes
Center thermostat defective?
(Check with evaporation test)
● Replace Center thermostat.
No
No
Switch lever has been properly adjusted?
● Adjust switch lever.
Yes
Usage correct?
● Too small or large in rice quantity.
● Too small or large in water quantity.
● Switched off once by hand in cooking
process.
● Switched off by shocks given in cooking
process.
● Rice not untied.
Keep warm function
● Warming fails (Warm lamp
not shown)
● Warming fails (Warm lamp
shown)
● Explain correct usage.
No
Micro switch change contact to NO (Warm
mode) after cooking is done?
● Adjust switch lever.
Yes
No continuity of warming heater?
8
● Replace warming heater.
SR-GA421/SR-GA281/SR-GA721
4. TESTING PROCEDURE
1. Bubbling test
Input the pan in the main body, and lightly rotate the pan clockwise and counter clockwise
to set the pan on the heating plate properly.
1. Fill water until the center area of the pan bottom is dipped, and close the lid. Then turn
on the boiling switch.
2. When it beings boiling to produce steam, remove the lid and immediately check the
bubbling condition on the pan bottom.
3. Bubbling condition is shown in figure 3.
A. Bubbles generate through out the circumference of the pan bottom ............... Proper
B. Bubbles does not generate on more than one quater part of the pan bottom
circuference .................................................................................................. Improper
Water Level
Water Level
Sheathed heater
Center thermostat
A
Figure 2
B
Figure 3
If it is improper, it may result from the insfficient contact between the pan bottom and
the sheathed heater. Check the pan bottom and the sheathed heater for foreign material
remained. Clean up the foreign materials or replace the parts.
2. Evaporation test
1. After satisfactory bubbling is confirmed, remove the lid and put a weight on the cooker.
2. Cover the entire pan bottom with 2 or 3 pieces of tissue paper (or gauze), and turn on
the switch subsequently.
3. The cooker is considered acceptable if the timing when steam generation comes to
a stop after water of the pan bottom has evaporated, is within 1 minute before and
after the cooking switch is turned off. If these requirements are not satisfied, check the
center thermostat as well as the contacted condition between the pan bottom and the
cooking heater, and then repair or replace the parts.
5 cm.
40
c
Pan (viewed from above)
Holes of
tissue paper
m.
Pan flange
section
COOK
WARM
Tissue paper
9
SR-GA421/SR-GA281/SR-GA721
4. TESTING PROCEDURE
3. Boiling control lever adjustment
Such a mechanical operation as center thermostat goes up and down is used to turn on
and off the micro-switch. Check and adjust this relationship as shown below.
When the boiling switch is turned on.
Checking
Adjusting
When the boiling switch is turned off.
The auxiliary lever presses the push- The auxiliary lever does not press
button (The “WARM” lamp comes on.) the push-button (The “COOK” lamp
comes on.)
To gain the above relationship, adjust the auxiliary lever by bending it with
long nose pliers.
10
SR-GA421/SR-GA281/SR-GA721
5. EXPLODED VIEW & PACKING VIEW
(SR-GA421/SR-GA281)
EXPLODED VIEW
(SR-GA421/SR-GA281)
11
SR-GA421/SR-GA281/SR-GA721
5. EXPLODED VIEW & PACKING VIEW
(SR-GA421/SR-GA281)
PACKING VIEW
(SR-GA421/SR-GA281)
12
SR-GA421/SR-GA281/SR-GA721
6. REPLACEMENT OF PARTS LIST & PACKING LIST
(SR-GA421/SR-GA281)
PARTS LIST
Ref.
No.
1
Part Name
LID ASS’Y
SR-GA421
Part No.
SR-GA281
Silver
White
White
White
White
Silver
HK
SINDBD
SINRBD
MAL
HK
HK
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
AQB01T29310U
AQB01T29410U
2
LID HANDLE
AQB10T2941K0
1
1
1
1
3
LID
AQB01T293
1
1
1
1
4
MEASURING CUP
ASR792-454BK
1
1
1
1
5
ALUMINIUM PAN
AQE50T293
1
1
1
1
AQB01T294
AQE50T294
6
THERMOSTAT ASS’Y
AQS00T293-0U
1
7
CAST HEATER ASS’Y
AQL20H17800U
1
ASR417-658-K
1
1
1
1
1
ASR416-658-K
1
ASR405-507
8
HANDLE FOR BOBY
AQE30T2941K0
1
1
1
1
AQE10T294
9
BODY COMPLETE
AQE13T2931WU
1
AQE13T2931UG
1
1
1
AQE13T2941WU
1
AQE13T2941UG
10
NAME PLATE
1
AQY50H299-UG
1
AQY50S299-WU
1
AQY50V299-WU
1
AQY50M299-WU
1
AQY50H300-WU
1
AQY50H300-UG
1
1
1
1
1
1
1
AQN10T294-W9
1
1
1
1
1
1
DECORATIVE PANEL
AQN21T294-W9
1
1
1
1
1
1
14
LAMP BOARD ASS’Y
AQN85T29310U
1
1
1
1
1
1
15
SWITCH LEVER COMP.
1
1
1
1
1
1
1
1
1
1
1
1
1
1
11
SWITCH ASS’Y
12
SWITCH PANEL
13
AQN00H299WU
AQN00H300W9U
AQN85T29410U
AQN30H299-0U
AQN30H300-0U
16
MICA HEATER ASS’Y
AQL70T29300U
17
WIRING TERMINAL ASS’Y
AQL92T294
18
BOTTOM PLATE ASS’Y
AQH20T2941WU
19
POWER CORD ASS’Y
AQQ00T29320U
1
1
1
1
1
1
1
1
AQL70T29410U
1
AQQ00H299-0U
1
AQQ00H300-0U
13
1
1
SR-GA421/SR-GA281/SR-GA721
6. REPLACEMENT OF PARTS LIST & PACKING LIST
(SR-GA421/SR-GA281)
PARTS LIST
Ref.
No.
Part Name
SR-GA421
Part No.
SR-GA281
Silver
White
White
White
White
Silver
HK
SINDBD
SINRBD
MAL
HK
HK
20
CORD BUSHING
ASR577Z658-K
1
1
1
1
1
1
21
SCOOP
ASR796-454AK
1
1
1
1
1
1
22
CAUTION LABEL (BODY)
ASR665T539-X
1
1
1
1
1
1
Silver
White
White
White
White
Silver
HK
SINDBD
SINRBD
MAL
HK
HK
LIST OF SCREW
Ref.
No.
Part Name
SR-GA421
Part No.
SR-GA281
A
TAPPING SCREW
XTN4+10BVW
2
2
2
2
2
2
B
SEMS SCREW
XYN5+C10FNS
1
1
1
1
1
1
C
TAPPING SCREW
XTN4+10BFJ
1
1
1
1
1
1
D
TAPPING SCREW
XTN4+10BFJ
4
4
4
4
4
4
E
SEMS SCREW
XTN4+C7FNS
8
8
8
8
6
6
F
TAPPING SCREW
XTN4+20BFJ
1
1
1
1
1
1
G
TAPPING SCREW
PK52-4871
1
1
1
1
1
1
Silver
White
White
White
White
Silver
HK
SINDBD
SINRBD
MAL
HK
HK
1
1
1
1
1
1
1
2
2
1
1
1
1
1
1
PACKING LIST
Ref.
No.
1
Part Name
PACKING CASE
SR-GA421
Part No.
AQZ01H299-$$
SR-GA281
1
AQZ01S299-$$
AQZ01H300-WU
2
OPERATING
INSTRUCTIONS
AQY00H299
1
AQY00S299
1
1
1
AQY00H299
3
UPPER PAD
4
PLASTIC SHEET
ASR756-631-K
1
1
1
1
1
1
1
1
ASR756T607-K
ASR758-631-K
ASR758T503AK
5
RUST PROOF PAPER
ASR758T613B
1
1
1
1
6
LOWER PLATE
AQZ16T2931
1
1
1
1
CORD PROTECTOR
AQZ15T2941
7
LOWER PAD
ASR752T607-K
1
1
1
1
1
1
8
PACKING PAPER
AQZ17T2931
1
1
1
1
1
1
ASR758T607B
14
SR-GA421/SR-GA281/SR-GA721
7. EXPLODED VIEW & PACKING VIEW
(SR-GA721)
EXPLODED VIEW
(SR-GA721)
15
SR-GA421/SR-GA281/SR-GA721
7. EXPLODED VIEW & PACKING VIEW
(SR-GA721)
PACKING VIEW
(SR-GA721)
16
SR-GA421/SR-GA281/SR-GA721
8. REPLACEMENT OF PARTS LIST & PACKING LIST
(SR-GA721)
PART LIST
Ref.
No.
Part Name
SR-GA721
Part No.
AQB01T29510U
White
White
White
White
MAL
SIN-DBD
SIN-RBD
USA
1
1
1
1
LID ASS’Y
2
LID HANDLE
AQB10T2941K0
1
1
1
3
LID
AQB01T2951
1
1
1
1QB01A298-0U
1
AQB01A298
1
1
4
MEASURING CUP
AQK00T295
1
1
1
1
5
PAN
AQE50T295
1
1
1
1
6
THERMOSTAT ASS'Y
AQS00T295-0U
1
1
1
1
7
CAST HEATER ASS'Y
AQL20T29510U
1
AQL20M298-0U
1
AQL20S298-0U
8
1
1
BODY HANDLE
AQE30T2951
2
2
2
2
9
BODY COMPLETE
AQE13T2951WU
1
1
1
1
10
NAME PLATE
AQY50M298-WU
1
AQY50V298-WU
1
AQY50S298-WU
1
AQY50A298-WU
11
SWITCH ASS’Y
1
AQN00M298W9U
1
1
1
AQN00A298W9U
12
SWITCH PANEL
13
DECORATIVE PANEL
14
LAMP BOARD ASS’Y
1
AQN10T295-W9
1
1
1
AQN21M298-$$
1
1
1
AQN85T29510U
1
1
1
1
ASR22W-590-K
AQN85A29800U
15
1
1
RICE COOKING LAMP
LEAD WIRE
AQN86T295
1
1
1
16
MICA HEATER ASS’Y
AQL70T295-0U
1
1
1
1
17
WIRING TERMINAL ASS’Y
ASR175T120A
1
1
1
1
AQL92T294
1
1
1
1
1
1
1
1
AQN86A298
18
BOTTOM PLATE ASS’Y
AQH20T2951WU
19
POWER CORD ASS’Y
AQQ00T295-0U
1
1
AQQ00M298-0U
1
1
AQQ00A298-0U
1
20
PROTECTING FRAME
HOLDER
AQE20T2951
4
4
4
4
21
PAN GUIDE
AQS22T2951$$
4
4
4
4
22
CAUTION LABEL
ARB32A298
1
17
SR-GA421/SR-GA281/SR-GA721
8. REPLACEMENT OF PARTS LIST & PACKING LIST
(SR-GA721)
LIST OF SCREW
Ref.
No.
A
Part Name
SR-GA721
Part No.
White
White
White
White
MAL
SIN-DBD
SIN-RBD
USA
TAPPING SCREW
XTN4+10BVW
2
2
2
2
B
P.F. HOLD SCREW
XYN4+C10FNS
4
4
4
4
C
SEMS SCREW
XYN5+C10FNS
1
1
1
1
XYN5+C10FNS
1
1
1
1
TAPPING SCREW
XTN4+8BFJ
2
2
2
2
E
TAPPING SCREW
XTN5+16BFJ
6
6
6
6
F
SEMS SCREW
XYN4+C7FNS
12
12
12
12
G
TAPPING SCREW
XTN4+20BFJ
2
2
2
2
H
TAPPING SCREW
XTN4+12AFJ
3
3
3
3
D
I
TAPPING SCREW
PK52-4871
1
1
1
1
J
TAPPING SCREW
XTN4+10AVW
1
1
1
1
PACKING LIST
Ref.
No.
1
Part Name
PACKING CASE
SR-GA721
Part No.
AQZ01M298-WU
White
White
White
White
MAL
SIN-DBD
SIN-RBD
USA
1
1
1
AQZ01A298-WU
2
1
OPERATING
INSTRUCTIONS
AQY00M298
1
1
1
3
UPPER PAD ASS’Y
ASR754A708
1
1
1
1
4
POLYETHYLENE SHEET
ASR762T590-K
1
1
1
1
5
RUST PROOF PAPER
AQZ48T295
1
1
1
1
6
CORD PROTECTOR
AQZ15T2951
1
1
1
1
7
LOWER PAD ASS’Y
ASR750A708
1
1
1
1
8
ROLL PAPER
AQZ17T295
1
1
1
1
AQY00A298
1
18
Download PDF