
1. DISPLAY AND OPERATION
B–63525EN/02
136
(1)Contrast adjustment
Potentiometer VRP1
This adjustment is made to compensate for variations between,
individual LCD adapters and LCD panels. When an LCD adapter or
panel is replaced, the following adjustment must be made. If the entire
LCD unit is replaced, however, no adjustment is needed.
(a) First, adjust potentiometer VRP1 until the displayed characters (all
black areas) appear white.
(b)Rotate the potentiometer in the opposite direction until the
characters appear clear and black.
(2)Flicker adjustment
Potentiometer VR1
This potentiometer is factory–set and normally need not be adjusted
by the user. If the setting is changed by mistake, re–adjust it according
to the following procedure. Note that some versions of this
printed–circuit board do not have this potentiometer; adjustment is
performed automatically.
(a) Using the check pins, observe HS and CLK on an oscilloscope.
(b)Over part of the range of potentiometer VR1, the positive–going
edge of HS will be almost in phase with the positive–going edge
of the CLK. Rotating the potentiometer a little does not change the
phase difference. Set the potentiometer to the midpoint of this
range.
(c) After completing the adjustment, confirm that the display does not
flicker.
HS
CLK
(3)Horizontal position adjustment
Switch SW1
This switch is factory–set and normally need not be adjusted by the
user. If the setting is changed by mistake, re–adjust it according to the
following procedure.
(a) Switch SW1 is used to move the display horizontally in units of
dots.
(b)Set the switch to the point between 8 and B where the entire display
is visible.
(c) The default setting is 9.
Adjustment procedure