U5" Malfunction Of Transmission Between Remote Controller And Indoor Unit - Panasonic Mini UM S Service Manual

Troubleshooting by Indication on the Remote Controller
4.39 "U5" Malfunction of Transmission between Remote
Controller and Indoor Unit
U5
Remote
Controller
Display
Applicable
AII indoor unit models
Models
Method of
In case of controlling with 2-remote controller, check the system using microcomputer is signal
Malfunction transmission between indoor unit and remote controller (main and sub) is normal.
Detection
Malfunction
Normal transmission does not continue for specified period.
Decision
Conditions
Supposed
Causes
Troubleshooting
150
Malfunction of indoor unit remote controller transmission
Connection of two main remote controllers (when using 2 remote controllers)
Defect of indoor unit PC board
Defect of remote controller PC board
Malfunction of transmission caused by noise
Be sure to turn off power switch before connect or disconnect connector,
Caution or parts damage may be occurred.
Using
YES
2-remote controllers
control.
NO
All indoor
NO
PC board microcomputer
monitors blink.
YES
Multi-core cable
YES
is used for the indoor
unit remote controller
transmission
wiring.
NO
SS1 of
YES
both remote controllers
is set to "MASTER."
NO
Operation
returns to normal when
NO
the power is turned off
momentarily.
YES
Mini UM S/M
Set one remote controller to
"SLAVE"; turn the power
supply off once and then back
on.
Replace indoor unit PC
board.
There is possibility of
malfunction caused by noise.
Check the surrounding area
and turn on again.
Switch to double-core
independent cable.
replacement
Defect of remote controller PC
board or indoor unit PC board.
Replace whichever is
defective.
(V2823)
Troubleshooting