Hitachi UC 18SD Technical Data And Service Manual page 11

(3) Failure Mode (C) steps and repair procedures
Abnormal heat is
generated.
Does the pilot
lamp go off
after completion
of charging?
Is the heat
generated by
the battery or
the charger?
Is the heat
generated by the
transformer?
Printed circuit board
is defective.
Replace printed
circuit board.
NO
YES
Warming of the battery in the
final stage of charging is normal.
Charger
YES
NO
Battery
--- 9 ---
To Failure Mode (B)
Replace battery.
Replace transformer.