Read Sharp R-2287 Service Manual online
11
R-2277
R-2287
R-2287
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
5. Stir the water to equalize temperature throughout the vessel.
6. Measure the final water temperature. (Example: The final temperature T2 = 21
6. Measure the final water temperature. (Example: The final temperature T2 = 21
°
C)
7. Calculate the microwave power output P in watts from above formula.
Initial temperature ............................................................................................... T1 = 11
°
C
Temperature after (25 + 3) = 28 sec (for R-2287) . ............................................ T2 = 21
°
C
Temperature after (35 + 3) = 38 sec (for R-2277) . ............................................ T2 = 21
°
C
Temperature difference Cold-Warm ...................................................................
∆
T = 10
°
C
Measured output power
The equation is “P = 170 x
The equation is “P = 170 x
∆
T” for R-2287 .......................... P = 170 x 10
°
C = 1700 Watts
The equation is “P = 120 x
∆
T” for R-2277 .......................... P = 120 x 10
°
C = 1200 Watts
JUDGMENT:
The measured output power should be at least
±
15 % of the rated output power.
CAUTION: 1
°
C CORRESPONDS TO 170 WATTS ( FOR R-2287) / 120 WATTS (FOR R-2277).
REPEAT MEASUREMENT IF THE POWER IS INSUFFICIENT.
WARNING: High voltages and large currents are present at the secondary winding and
filament winding of high voltage transformer. It is very dangerous to work
near this part when the oven is on. NEVER make any voltage measurements
of the high-voltage circuits, including the magnetron filament.
near this part when the oven is on. NEVER make any voltage measurements
of the high-voltage circuits, including the magnetron filament.
CARRY OUT 3D CHECKS.
Disconnect the leads to the primary winding of the high voltage transformer. Disconnect the filament
and secondary winding connections from the rest of the HV circuitry. Using an ohmmeter, set on a
low range, it is possible to check the continuity of all three windings. The following readings should
be obtained:
and secondary winding connections from the rest of the HV circuitry. Using an ohmmeter, set on a
low range, it is possible to check the continuity of all three windings. The following readings should
be obtained:
a. Primary winding
approx. 1.06
Ω
(R-2287)/ approx. 2
Ω
(R-2277)
b. Secondary winding
approx. 57.3
Ω
(R-2287)/ approx. 83
Ω
(R-2277)
c. Filament winding
less than 1
Ω
If the reading obtained are not stated as above, then the high voltage transformer is probably faulty
and should be replaced.
CARRY OUT 4R CHECKS.
and should be replaced.
CARRY OUT 4R CHECKS.
B
HIGH VOLTAGE TRANSFORMER TEST
1000g
1000g
1000g
T1˚C
T2˚C
Heat up for 28 sec. (for R-2287)
Heat up for 38 sec. (for R-2277)
Heat up for 38 sec. (for R-2277)
C
HIGH VOLTAGE RECTIFIER ASSEMBLY TEST
HIGH VOLTAGE RECTIFIER TEST
CARRY OUT 3D CHECKS.
Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be
tested using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal B+C
of the high voltage rectifier and note the reading obtained. Reverse the meter leads and note this
second reading.
Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be
tested using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal B+C
of the high voltage rectifier and note the reading obtained. Reverse the meter leads and note this
second reading.
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