Ricoh D131 Service Manual page 478

Laser synchronization detection error
The 1st laser synchronization detection unit could not detect the line
synchronization signal (DETP0) within 500 ms while the polygon mirror
D
motor was operating at normal speed.
Note: The unit polls for the signal every 50 ms. This SC is issued after
SC220 the 10th attempt fails to detect the signal.

Laser synchronization board connector loose, broken, defective

Laser synchronization detection board is not installed correctly (out
- of alignment)

Laser synchronization board defective

IPU defective
Laser Synchronization Detector Error: K Leading Edge (LD1)
While the polygon motor is rotating normally, no synchronizing
D
detection signal is output for black, leading edge for any LD other than
LD0.

SC221
Harness between the laser synchronizing detector and I/F unit is
disconnected, defective

Check all connections between LD unit, LDB, IPU
-

LD unit

LDB defective

IPU defective
FGATE ON error: K
The PFGATE ON signal does not assert within 5 seconds after
processing the image in normal job or MUSIC for start position [K].

Defective ASIC
SC230 D

Poor connection between controller and BICU.

Defective BICU

Check the connection between the controller board and the BICU.

Replace the BICU.

Replace the controller board.
SM Appendix 2-11
SC200: Exposure
D131/D132/D133