9. TROUBLE SHOOTING
Trouble
C h e c k point
Cause
T h e unit cannot be turned on.
None of the L E D s light up within 5
minutes after the power turned O N .
— T h e power cord is not connect-
ed or is broken.
— T h e power s w i t c h is defective.
— T h e f u s e is burnt.
E x c e s s i v e output
Neither the output voltage nor the
output current decreases.
— T h e power transistor is broken
or the control circuit is malfunc-
tioning.
Unstable output
1) Is there any change in the pow-
er voltage?
2) C a n any oscillation be observed?
3) Is any strong magnetic or elec-
tric field present near the unit?
1) T h e power voltage e x c e e d s the
limits of a rated input voltage.
2) Oscillation c a n be c a u s e d by
special t y p e s of loads.
3) T h e unit should be separated
from the oscillating source.
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