Application Of Silicon Grease To A Power Transistor And A Diode Bridge - Daikin 3MKS50E3V1B Service Manual

SiBE121135
6. Application of Silicon Grease to a Power
Transistor and a Diode Bridge
Applicable
All outdoor units using 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) is certainly applied to the heat radiation part (the contact point to the radiation fin) of
the power transistor and diode bridge.
Details The silicon grease is an essential article for encouraging the heat radiation of the power
transistor and the diode bridge. Applying the paste should be implemented in accordance with
the following instruction.
<Example>
The shape of electrical box and PCB vary depending on the model.
Trial Operation and Field Settings

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

∗1: Parts number of the silicon grease – 1172698 (Drawing number 3FB03758-1)
Note: There is the possibility of failure with smoke in case of bad heat radiation.
Wipe off the old silicon grease completely on a radiation fin.
Apply the silicon grease evenly to the whole.
Do not leave any foreign object such as solder or paper waste between the power transistor
and the radiation fin, and also 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
Paper waste
(R9056)
423