Mitsubishi MELDAS M600 Series, Maintenance Manual, Page: 28 / 61

3. TROUBLESHOOTING
3.2 Troubleshooting
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The LCD display is dark and the characters are not visible. The display is light and the characters are
not visible.
Cause Remedy
The contrast voltage is not
correctly adjusted. Turn the contrast voltage fine adjustment potentiometer
VR1 on the HR273 card, mounted on the rear of the
display, to the left and right, and check that the screen
appears correctly.
The LCD screen characters are light and hard to read.
Cause Remedy
The LCD contrast deviated due to
changes in the ambient
temperature. Adjust the contrast on the display's contrast adjustment
screen.
The LCD screen is disturbed and cannot be synchronized, or the characters are unrecognizable.
Cause Remedy
The card PC or HR121 card is
damaged. Contact the Mitsubishi Service Center.
(3) Problems related to operation section
A specific key switch does not function.
Cause Remedy
All key inputs do not function.
Cause Remedy
The F050 cable connected
between the operation section
key switches and the control
section is disconnected. Check the F050 cable connection.
The circuit in the HR111 card is
faulty. Contact the Mitsubishi Service Center.
The action differs from the operation.
Cause Remedy
Do not apply voltages other than those indicated in this manual on the connector.
Doing so may lead to destruction or damage.
Incorrect connections may damage the devices, so connect the cables to the specified
connectors.
Do not connect or disconnect the connection cables between each unit while the power is
ON.
Do not connect or disconnect the PCBs while the power is ON.
CAUTION