
19. MAINTENANCE FUNCTION
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(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.
NOTE If the ambient temperature is low, the brightness of the LCD de-
creases (immediately after the power is turned on, in particular).
This is due to the characteristics of the LCD, and does not indicate
a fault. As the ambient temperature rises, the LCD becomes
brighter.