Dewsensor - Panasonic REV-1 Service Manual

8-5. Dew Sensor
If excessive moisture or condensation is present inside the machine ( an internal humidity of more
than 98Yo)the unit will stop if running. Until the moisture level decreases only the Eject mode will
operate. To sense the humidity, a dew sensor is used. The sensor is a special variable resistor which
change resistance with ambient humidity.
The sensor ranges in resistance from about 5K ohm at 90Y0 humidity to about 50K omh at 98Y0
humidity. Normally, the voltage across the sensor is low because of its low resistance.
But if moisture condenses inside the unit, the SYSTEM CONTROL IC voltage of Dew terminal
increases to indicate a Dew condition.
Tape Mode Dew sensor ON Dew sensor OFF
Power
Compulsory Power on Power off
Dew indication Indicate "d" and "UI O" Normal indication
Cylinder Rotating *1 stop
OUT
Key operation Not possible *2
Possible
Cassette in immediately a cassette is
Possible
ejected after it goes to
cassette down position.
Power Compulsory Power on
Power off
Dew indication Indication "d" and "UI O"
Normal indication
Cylinder
Rotating *1 stop
IN Key operation Not possible *2
Possible
Cassette condition A cassette goes to down
Stand-by mode at STOP3
position and is in stand-by position.
mode.
"1: When the cylinder locks in dew
mode, it will be released until
dew sensor is truned off.
*2: The keys which do not relate to the tape running operation, are able to be used.
Dew sensor on: During Dew formation is detected and 80 minutes after completion of Dew
detection.
Dew sensor off: 80 minutes later after copmletion of Dew detection.
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