Toshiba MMU-P0121H Service Manual page 59

3-6-4. Diagnostic Procedure for Check Code
Check code
[04]
Inverter communication alarm
Is communication connector
between IPDU and interface
P.C. boards connected?
YES
Is there no disconnection
of communication cable
between IPDU and
interface P.C. boards?
NO
Is there voltage deflection
between 4 and 5 pins of
CN600 on interface P.C. boards?
[Measurement by tester :
DC 0 to 5V, 5 pin GND ]
YES
Is there voltage deflection
between 3 and 5 pins of
CN600 on interface P.C. boards?
[Measurement by tester :
DC 0 to 5V, 5 pin GND ]
YES
Check noise from outside, etc.
1. Connection error of communication cable between IPDU
and interface P.C. boards
2. Defective interface P.C. board
3. Defective IPDU P.C. board
4. Noise from outside
NO
YES
NO
NO
3-56
Operation cause
Correction of connector connection
On IPDU P.C. board : CN07
On interface P.C. board : CN600
Replace communication cable.
Interface P.C. board is defective.
IPDU P.C. board is defective.