Ricoh C211 Service Manual page 125

3.1.2 Black Level Adjustment: VT2300/VT2500
TP 601 waveform
TP 601 waveform
+l+f~
t
t
TP 600 standard black level
Adjust VR 2 so that the black level
is the same as the standard black level.
Purpose: To ensure that the black level from the CCD output
1.
2.
3.
4,
conversion/amplification board is the same as the standard black level
(1.4
v).
Close the scanner unit.
Press the Print Start key to turn on the fluorescent lamp.
Confirm that the black level at TP 601 is the same as the standard black
level (1.4 V) at TP600 on the A/D conversion board [A].
If the black levels are not the same, adjust VR2 to set the black level at
TP601 to the standard black level (1 ,4*0,03 V),
5-13