LG MH-1446SQP, Service Manual

Page: 13 / 35

5-3
• Microwave power output measurement is made with
the microwave oven supplied at its rated voltage and
operated at its maximum microwave power setting with
a load of (1000 ± 5)g of potable water.
• The water is contained in a cylindrical borosilicate glass
vessel having a maximum material thickness of 3 mm
and an outside diameter of approximately 190 mm.
• The oven and the empty vessel are at ambient
temperature prior to the start of the test.
• The initial temperature (T1) of the water is (10±2)°C. It
is measured immediately before the water is added to
the vessel. After addition of the water to the vessel,
the load is immediately placed on the center of the
turntable which is in the lowest position and the
microwave power switched on.
• The time T for the temperature of the water to rise by a
value
∆
T of (10±2)°K is measured, where T is the time
in seconds and
∆
T is the temperature rise. The initial
and final water temperatures are selected so that the
maximum difference between the final water
temperature and the ambient temperature is 5°K.
• The microwave power output P in watts is calculated
from the following formula:
4187 x (
∆
T) + 0.55 X (T
2
- T
0
)X M
T
• T
2
: Temperature after heating
• T
0
: Temperature after bowl
• M : Weight of bowl
is measured while the microwave generator is
operating at full power. Magnetron filament heat-up
time is not included. (about 3 sec)
• The water is stirred to equalize temperature throughout
the vessel, prior to measuring the final water
temperature.
• Stirring devices and measuring instruments are selected
in order to minimize addition or removal of heat.
WATER LOAD
TURNTABLE
MEASUREMENT OF MICROWAVE POWER OUTPUT
P =
DISASSEMBLY AND ADJUSTMENT
A. OUTER CASE REMOVAL
1) Disconnect the power supply cord from the outlet.
2) Remove the screws from the rear of the case.
The outer case must be moved backward to be lifted
off.
B. POWER SUPPLY CORD
1) Remove the outer case.
2) Disconnect two terminals and remove one screw of
the ground terminal.
C. CONTROL PANEL ASSEMBLY
1) Open the door.
2) Disconnect the leadwire from RELAY (RY2) of the
PCB SUB ASSEMBLY.
2) Disconnect the leadwire from connector (CN1) of the
PCB SUB ASSEMBLY.
3) Lift up and pull out control panel assembly carefully
from the cavity.
CAUTION: DISCHARGE THE HIGH VOLTAGE
CAPACITOR BEFORE SERVICING
(refer to page 2-1)
Remove the screw
Lift up and pull out control panel