Application Of Silicon Grease To A Power Transistor And A Diode Bridge - Daikin FTXS20K2V1B Service Manual

Application of Silicon Grease to a Power Transistor and a Diode Bridge

5. Application of Silicon Grease to a Power
Transistor and a Diode Bridge
Applicable
All outdoor units using an inverter type compressor for room air conditioner.
Models
When the printed circuit board (PCB) of an outdoor unit is replaced, it is required that silicon
grease (*1) be precisely applied to the heat radiation part (the contact point to the radiation fin)
of the power transistor and the diode bridge.
Details The silicon grease is essential for encouraging the heat radiation of the power transistor and the
diode bridge. Applying the grease should be implemented in accordance with the following
instruction.
<Example>
The shape of the electrical box and PCB vary depending on the model.
170
*1: Parts number of the silicon grease – 1172698 (Drawing number 3FB03758-1)
Note: There is a possibility of failure with smoke emission in case of bad heat radiation.
Wipe off the old silicon grease completely off the radiation fin.
Apply silicon grease evenly to the whole surface of the radiation fin.
Do not leave any foreign object such as solder or paper waste between the power transistor
and the radiation fin, or the diode bridge and the radiation fin.
Tighten the screws of the power transistor and the diode bridge, and contact to the radiation
fin without any gap.
Take out a PCB
OK : Evenly applied
silicon grease.
Power transistor
(TRM, TPM, IGBT, IPM, SPM, etc.)
Diode bridge
(Diode bridge, Rectifier stack, etc.)
Not applied.
NG : Not evenly NG : Foreign object
applied
SiBE041134
Paper waste
(R9056)
Trial Operation and Field Settings