Problems Detected At Tests And Suspected; Units - Ricoh A172 Service Manual

4. PROBLEMS DETECTED AT TESTS AND
SUSPECTED UNITS
(1) Problems detected at initial startup (power-on)
Problem
LCD shows nothing.
Diagnostic program is not
started ("Please wait" is
displayed).
(2) Problems detected at initialization (point accuracy calibration)
Problem
Pressing down on the touch
panel does not provide
reverse display.
NVRAM abnormality
message is displayed (when
calibration is skipped).
(3) Problems detected in self-diagnostic mode
Problem
Display is abnormal.
Menu cannot be selected.
A172/A199
Cause
LCD drive voltage is
abnormal.
Back-light is too dark.
Control signal to the LCD is
abnormal.
Start key detection is
abnormal.
Cause
Touch panel connector is
defective.
Analog voltage is not
detected.
Touch panel is defective.
A/D detecting section is
abnormal.
Detected data cannot be
obtained.
Point accuracy data for
back-up is cleared from
NVRAM.
Cause
LCD is defective.
Specified plotting data cannot
be written into video RAM.
Interrupt signal from the
touch panel cannot be
detected.
6-52
Suspected unit
Operation control unit
Op-ports 1 and 2
Op-ports 1 and 2
Operation control unit
Op-ports 1 and 2
Operation control unit
Suspected unit
Op-ports 1 and 2
Op-ports 1 and 2
Touch panel
Operation control unit
Operation control unit
ROM board
Suspected unit
LCD
Operation control unit
Operation control unit
SM