Canon LBP-CX Series Service Manual page 152

b. Flowchart 2
Connect the test probes of the
digital multimeter to the terminals
of the printer driver and laser
driver checker.
• red I ead to red terminal
• black lead to black terminal
Set the laser current switch (on
the control panel of the printer
driver and I aser driver checker)
to "MAX" without pressing
the laser power check button.
Measure the voltage of the digital
multimeter while pressing the
laser power check button.
Is the voltage
of the digital
multimeter within
110mV to 150mV
Switch the power OFF.
Turn VR202 fully counterclockwise.
Remove the 8-pin connector of the
printer driver and laser driver checker
and reattach the connector of the
laser unit to J204.
Return to the Basic Flowchart.·
Set the laser power select switch to
"LOW" without pressing the laser
power check button.
Measure the voltage of CP208 while
pressing the laser power check
button.
Set the laser power select switch to
"MED" without pressing the laser
power check button.
Measure the voltage of CP208 while
pressing the laser power check
button.
Set _the laser power select switch to
"HIGH" without.pressing the laser
power check button.
Measure the voltage of CP208 while
pressing the laser power check
button.
Did the
voltage of
CP208
increase gradually when the
aser power select switch is moved
rom "LOW" to "MED")!nd;"
'then to "HIGH"?
COPYRIGHT
©
BY CANON INC. CANON LBP-CX SERIES REV.2 JULY 1985 PRINTED IN JAPAN (IMPRIME AU JAPONJ
NO
NO
YES
YES
NO
Figure 7-15
From the Basic Flowchart
Unplug the connector of the laser
unit from J204 of the DC controller
PCB.
Connect the 8-pin connector of the
printer driver and laser driver checker
to J204. (See Figure 7-14.)
Set the laser power select switch to
"HIGH" and the laser current switch
to "STD". (Both are on the control
panel of the printer driver and laser
d(iver checker.) Turn VR202 fully
counterclockwise.
Switch the power ON.
Measure the voltage of CP208 on the
DC controller PCB while pressing the
laser power check button (on the
control panel of the printer driver and
and laser driver checker).
Switch the power OFF.
Replace the DC controller PCB.
Printer driver
and laser driver
checker
Connector
(10 pin)
Connector (8 pin)
+
+ lead
-
lead
Figure 7-14
Turn VR202 a little clockwise
without pressing the laser power
check button.
Measure the voltage of CP208
while pressing the laser power
check button.
YES
NO
NO
DC controller PCB
J205
J204
DVM
c:J
+
Turn VR202 a little counter-
clockwise without pressing the
laser power check button.
Measure the voltage of CP208
while pressing the laser power
check button.
YES
NO
7-11