7-12 
the panel of the instrument and the 
backplane (backplane socket position: J6 
socket on the left). 
3. If the problem persists, replace the status 
screen control board (refer to 11.1.5). 
Aux O2/AIR 
Comm Stop 
High 
The CPU board lost 
communication with 
the auxiliary O2/air 
module for 10s. 
1. Restart the auxiliary O2/air module. 
2. If the problem persists, remove the 
auxiliary electrical outlet (refer to 8.1.2) and 
service door (refer to 8.1.1), reconnect the 
cable between the auxiliary O2/air module 
and the backplane (backplane socket 
position: "O2Air" socket on the right). 
3. If the problem persists, replace the 
auxiliary O2/air module (refer to 11.1.4). 
HFNC Module 
Comm Stop 
High 
The CPU board lost 
communication with 
the HFNC module 
for 10s. 
1. Restart the HFNC module. 
2. If the problem persists, remove the 
auxiliary electrical outlet (refer to 8.1.2) and 
service door (refer to 8.1.1), reconnect the 
cable between the HFNC module and the 
backplane (backplane socket position: 
"O2Air" socket on the right). 
3. If the problem persists, replace the HFNC 
module (refer to 11.1.4). 
 
 
7.3.3 Power Board Runtime Alarms 
Power System 
Comm Stop 
High 
The CPU board fails 
to communicate with 
the power board for 
10s. 
1. Restart the anesthesia machine. 
2. Open the display cable cover (refer to 
8.1.7), reconnect the display cable, open the 
service door (refer to 8.1.1), and reconnect 
the cable between the backplane and display 
(J5 socket at the lower left part of the 
backplane). 
3. If the problem persists, open the service 
door (refer to 8.1.1), disconnect the internal 
battery cable at the lower left part on the 
rear of the cart. Restart the machine 5 
minutes after the power board is powered 
off. 
4. Select Setup > Service > Data 
Monitors > Power System and check 
whether valid data is available for the A/D 
channel. (If data is invalid, "---" is 
displayed.) If yes, a software error has 
occurred. In this case, upgrade the software 
(refer to Chapter 6). 
5. If the problem persists, replace the 
DC-DC power board (refer to 11.1.11). 
6. If the problem persists, replace the cable 
between the backplane and display. 
7. If the problem persists, replace the CPU