Trouble Shooting Guide - Panasonic MC-E780 Service Manual

TROUBLE SHOOTING GUIDE

CONDITION
Motor fails to rotate.
(no noise is heard
at all).
Motor runs but
does not suction.
Noise or vibration.
Motor does
not change power.
(Runs always
at full speed)
Motor runs
irregularly.
NOTE: Parts marked (*)only affect to mdels MC-E781 and MC-E783.
CHECKPOINT
Power cord
connection.
Motor continuity.
Carbon brushes.
ON/OFF Switch.
Thermal cut-out.
Triac.
Power control circuit.
*Sliding potentiometer.
Trimmer Potentiometer
(VR1)
Hose or Suction inlet.
Dust bag / Central filter.
Motor fan
*Sliding potentiometer.
Power control circuit
* Sliding potentiometer
METHOD OF INSPECTION
Check power cord continuity between
plug pins and contact base.
Check motor continuity between carbon
brush holder tabs.
Check if there is gap between
carbon brush and conmutator.
Check continuity across switch
connections.
Check continuity across
thermal cut-out tabs.
Check if the triac is in open circuit.
Check if the diac is in open circuit.
Check if the potentiometer is in
open circuit or if the lead wires
connection are not correct.
Place the sliding potentiometer at min.
power and check if the potentiometer
(VR1) is adjusted at 450W.
Check if there is any blockage
in the hose or suction inlet.
Check if dust bag is full or dust
accumulated in central filter.
Check dust accumulated in motor fan
(it could happen if the vacuum cleaner
has been used with a broken dust bag
or without central filter).
Check if the potentiometer is
short-circuited
Check if the power control circuit is
short-circuited.
Check possible bad contact of the
sliding potentiometer tabs.
18
CAUSE / REMEDY
If there is no continuity,
replace the power cord.
If there is no continuity, replace
the motor.
If there is gap between carbon
brush and conmutator, replace
both carbon brushes.
If there is no continuity, replace
ON/OFF switch.
If there is no continuity,
replace thermal cut-out.
If it is in open circuit, replace it.
replace power control circuit.
If it is in open circuit,
replace power control circuit.
If it is in open circuit, replace it.
If the lead wire connections
are not correct, repair them.
If it is adjusted at 450W
and the motor doesn't work,
replace power control circuit.
If there is any blockage,
remove it.
If the paper bag is full, replace it.
If the central filter is dirt,
clean or replace it.
If there is dust accumulated in
motor fan, replace the motor and
check filter condition. (never try to
dismantle the motor fan).
If it is short-circuited, replace it.
If it is short-circuited, replace it.
If there is bad contact,
replace the sliding potentiometer.