Maintenance Data; Trouble Shooting - Mitsubishi Heavy Industries SRK25GZ-L1 Handbook

SCM-C
7.6

MAINTENANCE DATA

7.6.1 Trouble shooting

(1) Trouble shooting to be performed prior to exchanging PCB, (Printed circuit board) [Common to all models]
All the models described in this chapter are controlled by a microcomputer. When providing maintenance service to customers it
is necessary to understand the function controlled by a micro computer thoroughly, so as not to mistakenly identify correct operations
as mis-operations. It is also necessary to perform the following simple checks before conducting detailed checks or exchanging
printed circuit board.
Claim call from the user
Ascertain the nature of the claim.
Ascertain the operation status.
Is this nonsense claim?
NO
Operate the unit.
Does the trouble occur again?
YES
Temporarily turn off the power source
and turn it on again in about 1 min. and
turn the unit on again.
Does the trouble occur again?
YES
Disconnect connectors and connect them
again.
Operate the unit again after confirming that the fuse
and the varistor equipped on PCB does not burn
out.
Does the trouble occur again?
YES
Carry out checks according to detailed
check process (See later page)
260
Before exchanging Printed circuit board
YES
NO
NO
NO
Unit did not cool, etc.
¡ Is the power on?
¡ Is the thermostat setting correct?
(Not too high?)
¡ Is the unit in a timer operation?
¡ Does user understand function?
etc.
¡ Explain the function of the unit to user.
No need for PCB change
Check further the status when the trouble Occurred
(such as the timer of occurrence, power failures,
thunder, use status of other electrical appliance, etc).
Clarify the reason for the problem and explain it
thoroughly to the user.
No need for PCB change
Microcomputer runaway due to power source
conditions is a possible cause.
No need for PCB change
The cause is defective connector contact.