Panasonic Rice Cooker Sr Ga721 Srga281 Srga421 Operating Instructions

Service Manual
Order No. PHAT070510C3
Automatic Rice Cooker
SR-GA421/SR-GA281/SR-GA721
EXPORT
©  2007  Panasonic  Home  Appliance  (Thailand)  Co.,Ltd 
All  rights  reserved.  Unauthorized  copying  and  distrbution  
is a violation of law. 
Specification 
Specification subject to change without notice. 
ModelSR-GA421SR-GA281SR-GA721Detail
CountryHKSIN-DBDSIN-RBDMALAYSIAHKMALAYSIASIN-DBDSIN-RBDUSA
Power Source220 V / 50 Hz 230 V / 50 Hz220 V / 50 Hz240 V / 50 Hz220 V / 50 Hz240 V / 50 Hz230 V / 50 Hz...

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SR-GA421/SR-GA281/SR-GA721

WARNINGThis 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...

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SR-GA421/SR-GA281/SR-GA721

L
N
MICA HEATER ASS’YCAST HEATER
LAMP RESIST
.
T.F.
INPUT SWITC
H
LAMP RESIST.
KEEP W ARM NEON LAMP 
(BIG)
(SMALL
)
E
Green
RICE COOKING NEON LAMP 
Lamp Lead Wire A (Orange) Lead Wire (Orange)
Lamp Lead Wire C (Brown) 
Twist one time
Lamp Lead Wire B (Gray) 
Lever Earth Lead Wire (Green)
Silicone Tube (Blue)
N
T
wist two time
Thermal Fuse Wire (Gray)Switch Lead Wire (Blue)
Cord Wire Earth (Green)Silicone Tube (Green)
Silicone Tube (Brown)
Cord Bush10˚±5˚
Thermal Fuse Wire...

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SR-GA421/SR-GA281/SR-GA721

Cord Wire Earth (Green)
Cord Wire Blue (N) Cord Wire Brown (L)Heater lead wire B (grey)
Thermal fuse lead wire (Blue) Thermal fuse lead wire (Grey
)
User position Heater lead wire C (Brown)
Heater lead wire A (Red) Grey
Brown
Red
Cathode lead wire (Brown
)
Keep warm lamp lead (Red
)
10˚±5˚
MICA HEATER ASS’Y
CAST HEATER
LAMP RESIST.
SWITCH
LAMP RESIST.
KEEP WARM NEON LAMP 
RICE COOKING NEON LAMP 
(SMALL)
(MIDDLE)
(BIG)
E
GreenINPUT
L
N
Brown
Blu
e
1.F.T2.F.T

1. SCHEMATIC...

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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.
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...

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SR-GA421/SR-GA281/SR-GA721

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 case
s 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...

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SR-GA421/SR-GA281/SR-GA721

3. TROUBLESHOOTING GUIDE
SymptomDiagnosisRemedy
Cooking function
● Cooking fails (Cooking 
lamp is not shown)
No continuity of cord?Yes ● Replace AC cord. 
No continuity of thermal fuse? Yes
 
● Locate cause for fusing and 
replace fuse. 
No continuity of micro switch?
Yes
 
● Replace 
Frame ass’y. 
Center thermostat is broken?
(Checked evaporation test) Yes
 
● Replace center thermostat. 
Switch lever properly adjust?
No 
● 
Adjust Switch lever. 
● Cooking fails (Cooking...

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SR-GA421/SR-GA281/SR-GA721

3. TROUBLESHOOTING GUIDE
SymptomDiagnosisRemedy
● Earlier Switching-off
● Poor cooking finish
Too hard
Too soft
Half-boiled
Poor contact between pan and sheathed 
heater? (Check with bubbling test)Yes 
● Replace pan or sheathed 
heater.
 
Center thermostat defective?
(Check with evaporation test) Yes
 
● Replace Center thermostat. 
Switch lever has been properly adjusted?
No 
● Adjust switch lever. 
Usage correct?
● Too small or large in rice quantit
y.
● Too small or large...

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SR-GA421/SR-GA281/SR-GA721

4. TESTING PROCEDURE
1. Bubbling testInput 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...

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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. When the boiling switch is turned off.
 
CheckingThe auxiliary lever presses the push-
button (The “WARM” lamp comes on.)The auxiliary lever does not press 
the push-button (The “COOK” lamp 
comes on.)
AdjustingTo...