Samsung AM072/096/120/144FXVAFH, Service Manual

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Troubleshooting
Samsung Electronics 4-27
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Essential Requirements before PCB Changes in Case of Communication Error Occurrence
1. Find the communication IC near the communication terminal.
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Indoor Unit
- Above Red Connector : Communication IC between indoor and outdoor units.
- Above Blue Connector : Communication IC for cable remote control.
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Outdoor Unit
- When there is module communication as in PLUS II and PLUS III –
Above Red Connector of Main Unit : Communication IC between indoor and outdoor units.
- When there is no module communication as in PLUS II and PLUS III –
Above Yellow Connector of Each Unit : Communication IC between outdoor units.
- Other Outdoor Unit- Above Communication Connector : Communication IC between indoor and outdoor unit.
2. Measure the resistance of the communication IC.
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Measurement Method : Measure the No.5 - No.6 Pin resistance
Measure the No.5 - No.7 Pin resistance
Measure the No.5 - No.8 Pin resistance
3. Normal and defective judgment is tested for communication
IC by using measured resistance.
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Judging as Normal
- Each resistance value should be measured in tens of kΩ~to hundreds of kΩ.
- Difference between the two resistance values should be of some number of kΩ.
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Judging as defective
- One or both are low with tens of Ω
- One or both of them is open
Display IC No. 1 pin
No.5 No.6 No.7
Indoor Unit
Outdoor Unit
Outdoor unit
communication between
Indoor Unit communication
Transmitter communication