SERVICE MANUAL
5–60
10FEB97 – SM3226-1
Laser Diode Control Board
Setting Laser Diode Control for D-Min
Use this procedure when the Internal Test Print contains random, black dots in the D-MIN area, or if horizontal black
lines appear on the test print. This adjustment is required to set D-Min to just above the threshold current of the Laser
Diode, which is seen at TP17.
Note
There are 3 styles of the LASER DIODE CONTROL BOARD. These BOARDS are STYLE -02/-03 and STYLE -
07. STYLE -07 does not have a PORCH BOARD.
To Check:
[1] De-energize the LASER PRINTER.
[2] Remove the TOP COVER. If necessary, see the procedure on Page 2–5.
[3] Loosen the 5 SCREWS and remove the LASER
DIODE CONTROL BOARD COVER.
[4] Connect one 10X Probe TL-2074 to the Channel A input of the Oscilloscope TL-3348.
[5] Connect a second 10X Probe TL-2074 to the Channel B input of the Oscilloscope TL-3348.
[6] Set the Time Base to 50ns/div.
[7] Set the Voltage to 500 mV/div.
[8] Set the Trigger to Ch. A, +slope.
[9] Set the LDC Board Switches as noted in the table at the right.
STYLE -02/-03
STYLE -07
SW1: 3
SW2: 3
SW2: 3
SW3: 3
DSW1: 0
DSW2: 0
DSW3: 0
H129_0015AC
COVER
BOARD
CONTROL
LASER DIODE
SCREW(5)
H129_0015ACA
