44473001TH  Rev.1 
244 /
Oki  Data  CONFIDENTIAL
7. TROUBLESHOOTING PROCEDURES
7.5.4. (18) Humidity sensor error (error code 123)
(18-1) Humidity sensor error
Check item Check operation
Actions for NG 
results
(18-1-1) Check the system connection
Connection to the 
CU/PU board and 
to the toner sensor 
board
Check if the 16-conductor FFC is connected 
to the SSNS connector 
 of the CU/PU board 
normally.
Check if the 16-conductor FFC is connected to 
the SSNS connector 
 of the toner sensor board 
normally.
Re-connect the 
cable normally.
FFC connecting the 
CU/PU board and 
the toner sensor 
board
Check for open-circuit with VOM. 
Check that peeling off of sheath does not occur 
in any cables by visual inspection.
Replace the 
FFC with the 
normal FFC.
Check item Check operation
Actions for NG 
results
(18-1-2) Environment condition
Sharp change 
of environment 
condition
Is the environment condition changed sharply 
from a low temperature environment to a high 
environment condition within a short time? 
(Example is such a case that a printer is moved 
from storage condition of a cold area in winter to 
an office environment.)
Leave a printer 
for around one 
hour in the new 
environment 
to get used 
to the new 
environment. 
After that, turn 
on the power 
again. 
Before turn 
on the power, 
touch the metal 
panel of the 
controller panel 
and the metal 
plate inside a 
printer to feel 
temperature 
increase 
inside a printer 
with human 
hands. After 
confirmation 
that the printer 
temperature 
has increased 
close to 
the room 
temperature, 
turn on the 
power again.