Janome NH40 Service Manual page 27

Buzzer sounds after few seconds when the self-diagnostic test has been finished.
The test result has been determined.
The defective part number.
See page 22-24 "Steps and
items" section.
Turn the power switch off when the self-diagnostic test is finished.
Correct:
Buzzer sounds and LCD displays "00"
Defective:
Caution buzzer sounds and LCD displays the defective part
number. Refer to page 22-24 and fix the defective part.
25