Electrolux MCC4060E Service Manual page 21

PROCEDURE
LETTER
B HIGH VOLTAGE TRANSFORMER TEST
SOI 12.06 FV
TEST PROCEDURES
Measuring method:
1. Measure the initial temperature of the water before the water is added to the
vessel. (Example: The initial temperature T1 = 11°C)
2. Add the 1 litre water to the vessel.
3. Place the load on the centre of the shelf.
4. Operate the microwave oven at HIGH for the temperature of the water rises
by a value ΔT of (10 ± 2) K.
5. Stir the water to equalize temperature throughout the vessel.
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.
Room temperature ................T0 = 21°C Initial temperature............. T1 = 11°C
Temperature after (47+ 3) = 50 sec................................................... T2 = 21°C
Temperature difference Cold-Warm.................................................ΔT1 = 10°C
Measured output power
The equation is "P = 90 x ΔT" .................................. P = 90 x 10°C = 900Watts
JUDGEMENT: The measured output power should be at least
the rated output power.
CAUTION: 1°C CORRESPONDS TO 90 WATTS. REPEAT
MEASUREMENT IF THE POWER IS INSUFFICIENT.
WARNING: High voltages and large currents are present at the
secondary winding and filament winding of the 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.
CARRY OUT 3D CHECKS
Disconnect the leads to the primary winding of the power 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:-
a. Primary winding ............................approximately 2
b. Secondary winding ....................approximately 127
c. Filament winding ..................................less than 1
If the reading obtained are not as stated above, then the power transformer is
probably faulty and should be replaced.
CARRY OUT 4R CHECKS
COMPONENT TEST
Heat up for 50 sec.
21/43
±
15 % of
Ω
Ω
Ω
599 37 42-75