EPSON AcuLaser C1900/AcuLaser C900 Revision B
Troubleshooting Status Display (AcuLaser C1900) 129
ERROR CODE: E024 
“FUSER ROLLER TEMPERATURE INCREASE PROBLEM”
ERROR CODE: E025 “FUSER ROLLER LOW TEMPERATURE PROBLEM”
 Detection Timing
When 80°C is not reached in 100 seconds after start of warming up.
When the fusing roller temperature has dropped and remained below 70°C for 10 
seconds during standby.
 Solution
 Electric parts which can cause the trouble:
• Fusing Roller Heater Lamp (H1)
• Pressure Roller Heater Lamp (H2)
• Thermostat (TS1)
• Engine Board (PWB-A)
• Power Supply Unit (PU)
ERROR CODE: E026 
“FUSER ROLLER HIGH TEMPERATURE PROBLEM”
ERROR CODE: E027 “FUSER ROLLER THERMISTOR PROBLEM”
 Detection Timing
When the Fuser Roller temperature is 220°C or higher for 0.1 second.
When between 40 seconds and 50 seconds after start of warming up of the Fuser 
Roller, the Fuser Roller temperature does not rise for one second by 5
°
C from that at 
start of fuser warming up.
 Solution
 Electric parts which can cause the trouble:
• Thermistor (TH1)
• Engine Board (PWB-A)
Table 3-14.
Step Check Item
Yes/
No
Remedy
WARNING 
DIAGRAM
Control Signal
1 Check the continuity of H1 
and H2.
NO Replace the H1, H2. -
2 Check the continuity of TS1. NO Replace the TS1. -
3 Check to see if the resistance 
of TH1 is infinite.
(Between CN18-1 and 2 on 
thermistor side)
YES Clean TH1 or replace 
the Fuser Unit.
HEATER
NO Replace the PU.
Replace the PWB-A.
Table 3-15.
Step Check Item
Yes/
No
Remedy
WARNING 
DIAGRAM
Control Signal
1 Check to see if TH1 is 
shorted.
(Between CN18-1 and 2 on 
thermistor side)
YES Clean TH1. HEATER
Replace the Fuser Unit.
NO Replace the PU.
Replace the PWB-A.