Circuit Protection Element; Replacing The Flexible Card Wires - Sony PMW-EX30 Service Manual

1-12-5. Circuit Protection Element

The DPR-297 board of this unit is equipped with the positive characteristics thermistor (power thermistor)
as the circuit protection element. The positive characteristics thermistor limits the electric current fl owing
through the circuit as the internal resistance increases when an excessive current fl ows or when the ambi-
ent temperature increases. If the positive characteristics thermistor works, turn off the main power of the
unit and inspect the internal circuit of this unit. After the cause of the trouble is removed, turn on the main
power back again. The unit works normally. It takes about one minute to cool down the positive charac-
teristics thermistor after the main power is turned off.
Board Ref. No.
DPR-297 THP700 to THP703

1-13. Replacing the Flexible Card Wires

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The fl at cables, fl exible card wires and boards are used to connect between the following boards. Life of
fl exible card wire will be signifi cantly shortened if it is folded. Be very careful not to fold the fl at cables,
fl exible card wires and boards.
Because the direction of the fl at cables, fl exible card wires and boards are different depending on the
shape of the connector, be careful when connecting the fl at cables, fl exible card wires and boards.
Disconnecting
1. Turn off the power.
2. Slide or lift up the portion A in the direction of the arrow to unlock and pull out the fl exible card wire.
Connecting
m
. Do not insert the coaxial cable with connector sideways.
. Check that there is no stain or dust on the contact surface of the coaxial cable with connector.
1. Slide or lift up the portion A in the direction of the arrow and securely insert the fl exible card wire
into the deep end of the connector.
2. Return the portion A to its original position and lock the connector.
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When connecting the fl exible card wire, check the connec-
tor shape, and great care should be taken for the direction
of the contact surface or isolation surface (blue).
PMW-EX30
Address Protection circuit/equipment
A-4 Internal circuit of the board
Isolation surface
(blue)
A
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