Hitachi uc 24yfb Technical Data And Service Manual page 21

(4) Trouble mode (D)
Pilot lamp flickers red,
indicating abnormality.
sort of conductive foreign
matter in the hole where the
Is the battery short-circuited
Faulty internal circuit
NO
Is there some
battery is inserted ?
NO
or opened ?
NO
Replace PCB.
YES
Remove foreign matter.
YES
Replace the battery.
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