Cautions On Replacement Of Pcb Boards - Pioneer WYD-GLFI SERIES Service Manual

Wd indoor / yn outdoor units series dc inverter air conditioner dc inverter split wall-mounted ductless heat pumps

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Table Of Contents

Table of Contents

Switching power output of power

source board

Communication signal of power

source board and module board

Electronic expansion valve control

signal

Electronic expansion valve socket

Communication

between

source board and PFC board

Communication between nodule

board and PFC board

Base Auxiliary heating

1, Directive for Replacement of Inverter Module

When replacing Mitsubishi inverter module, the technician must take care on the operating process

for replacement of inverter module. Special care shall be taken to ensure the coating quality of

thermal grease. The detailed directive is as follows:

1. Before replacing the inverter module, make sure to eliminate the old thermal grease and

foreign particles with soft clean cloth before you can apply the new thermal grease. Always

use the thermal grease provided by the customer service department or the same silicone

grease as used in the factory. Never use any other product of poor quality. Operate in strict

accordance with the guideline.

2. Ensure that the thermal grease (silicone grease) is applied thin, flat and even. Use plastic

scraper to apply the grease. Firstly, place a tiny quantity of thermal grease at the center of the

place where the grease is to be coated. Then, use the plastic scraper to apply the grease at the

center slightly and evenly onto the entire surface to be treated. In consideration of the

deviation in the levelness of radiating fin, the thickness of thermal grease must be 0.1mm (for

small area) to 0.3mm (for large area), depending on the size of radiating area.

Note: The function of thermal grease is to fill up the gap and let the surface tightly adhered. It

is not true "the more the better".

3. Before placing the greased module flatly onto the radiating fin to tighten the screws, firstly

hold down with the hands; then press and move back and forth slightly until it is in full contact

before tightening the screws. When tightening the screws, take special care on the strength of

radiator materials when using the electric screwdriver, torque screwdriver or torque wrench.

Ensure that the screws are correctly tightened to position. The tightening force varies with the

module.

4. Cautions on installation of screws on inverter module: If the tightening force is applied

extremely unbalance`d during installation of the module onto the radiator, the silicon chip

inside the module may be deformed due to the stress. And this might cause damage or degrade

to the module. Therefore, be sure to operate according to the required tightening sequence.

The recommended tightening sequence for the inverter module fixed by two screws is as shown

CN4

CN5

CN6

CN7

power

CN9

CN8B(Module

board)

CN11