Toshiba MCY-MHP0404HS-E Service Manual page 175

4. Replacement steps
(1) Turn off the power of the outdoor control unit. (Turn off the power of the outdoor unit.)
(2) Immediately after turning off the power of the outdoor unit, the electrolytic capacitors inside the unit will still
have a high voltage, and there is a risk of electric shocks. Therefore, wait at least 5 minutes after turning off
the power before starting the replacement procedure.
(3) Disconnect all the screws ② and connectors which are connected to the malfunctioning fan IPDU P.C. board.
(Since the connectors may be damaged if they are pulled out by grasping their lead wires, be sure to take
hold of the connectors themselves when disconnecting them.)
(4) To remove the malfunctioning fan IPDU P.C. board, remove the four card spacers ③
(When removing the fan IPDU P.C. board, take care not to damage any of the four card spacers ③. If a
card spacer ③ has been damaged, be sure to use a card spacer ③ packed with the board, and replace the
damaged card spacer by following the steps in the service manual. Failure to replace it may cause the fan
IPDU P.C. board to malfunction.)
(5) The removed screws ② will be used again when the service P.C. board is installed so keep them in a safe
place to ensure that they will not be lost or misplaced.
(6) When replacing the board, evenly apply silicone heat sink compound to the heat-sink surfaces of the IPM
apply the silicone heat sink compound may cause the service P.C. board to malfunction.
(7) When replacing the board, use the removed screws ② (M3x20) to connect the disconnected lead wires
following the wiring diagram display panel.
(Check that the wires have been inserted correctly and securely to prevent connection errors.)
(8) If screws ②
will deteriorate, possibly causing malfunctioning so pay attention when tightening the screws.
However, under no circumstances must power-driven screwdrivers or air screwdrivers be used when
installing the replacement P.C. board. Using such a device may damage the components. (Screw tightening
(9) If any of the components on the P.C. board have been bent in the course of the replacing the board, rework
them so that they do not come into contact with the other components.
(10) Install the cover, turn on the power, and check operation.
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