Hitachi HT-4139-28 Maintenance Manual page 100

■ Replacing the Prism (PC21 Sensor), the PC 22 ASSY (PC22 Sensor), the Prism (PC31 Sensor)
① Remove the Main Cover, the Side Cover, and the Back Cover. For instructions, please refer to "8.1
Preparation" for instruction
② Remove the Guide (Lower Mirror), the Cover Sheet. For instructions, please refer to "8.3.13 Replacing the
Lower Mirror ASSY"
③ Unscrew 6 bind-head screws on the Upper Guide and remove the Upper Guide.
Caution: When removing the Upper Guide ASSY, disconnect the cable connector on PC22 and unlock
the locking wire saddle.
④ Remove the Sensor
- Unscrew 1 hexagonal screw on the Prism (PC21 Sensor), and remove the Prism (PC21 Sensor)
- Disconnect the connector on PC22 ASSY (PC22 Sensor) from the middle connector. Unscrew 1 countersunk
screw from the Upper Guide ASSY, and remove the PC22 ASSY (PC22 Connector)
- Unscrew 1 hexagonal screw on the Prism (PC31 Sensor) and remove the Prism
⑤ Attach the new Sensor
⑥ Take the reverse steps to attach the Sensor
⑦ After replacing the part, run Auto Calibration Test
#57 Purism
（PC31）
Bind head screw
Bind head screw
#34 PC22_ASSY
（PC22）
hexagonal screw
#34 PC22_ASSY
（PC22）
Tools Needed: Magnetic Philips Screwdriver (No.2)
Bind head screw
Bind head screw
Bind head screw
Upper Guide ASSY
countersunk screw
REV0 10.02.15
Bind head screw
hexagonal screw
#57 Purism
（PC21）
-H8-37-