position.
(6) Fix the control panel on the oven
(7)
in the terminal
of the PC board.
5
AND THE
OF
Before overhauling a microwave
you should judge the breakdown and the cause
then you can
repair it with corresponding ways. The overhauling
be proceed in order, any hasty
is not
recommendable,
over-working
be done when repair. The microwave oven may occur
breakdown due to
kinds of
thus, when overhaul, they
should be taken into consideration.
Special attention must be given to the microwave leakage and the electric insulation when examine because they
may do harmful to the repairing
5.1
THE BREAKDOWN CAUSES.
How to examine a microwave oven with breakdown? A
demonstrated in practical operating
through inspecting and listening. On the basis of
amounts of perceptual
you can judge and
analysie the break down quickly and correctly.
5.1.1 INSPECTION.
Inspect whether the oven shape is disordered and where is the disordered
any. It is normal if the
cabinet disordered a
but abnormal if the oven, the door disordered, the door hook broken, the door crooked,
or there
too much looseness
the door and the oven
the door is closed .
5.1.2
Listening to the sound of the oven operating and the noise of the fan. Minor "wen wen" noise,
and
noise should be considered as normal. But it is abnormal if the following noises occur:
(1) Sound "wen wen noise.
(2) Long time "shishi" noise.
(3) Strike sound
"Pipa pipa"
5.2 SPOT
STEPS OF THE
OVEN
5.2.1
THE
RESISTANCE
the insulating resistance with a avometer or a
megaohmmeter the value should not be less than 2 megaohms.
Otherwise,
examination should be taken at once. Such as
checking whether the motor, the thermal cutout, the transformer or
the capacitor
electricity
5.2.2
OF THE RESISTANCE VALUE OF THE
OVEN.
the door, set the time (the oven is at operating condition but
the power
haven't been plugged in ), measure the
feet (L -
N) of the power
with
grade of an avometer, the resistance value should be about 2.5
If open circuit
occurs, then you must check whether the 8A fuse is
the
winding of the transformer is open
the thermal cutout is open circuit or
you must check whether the interlock device is put through or all
the plugs
connected
If
circuit occurred or the
resistance less than 1.5
you should check whether the
primary winding of the power transformer is short - circuited or part
5.2.3
OF
LEAKAGE.
Measure the microwave leakage with a microwave leakage measure.
16
Fig. 5-1
