Part No.: 9707278019 (Active Filter Module)
Purpose: To verify the electrical integrity and output performance of the AFM, which controls power factor and DC voltage supply to the outdoor unit inverter circuit.
Check Point 1: Open / Short-Circuit and Diode (D1) Inspection
Procedure
Disconnect power and remove the connector from the Active Filter Module.
Using a digital multimeter, check for open or short circuits between terminals.
Measure diode resistance in both forward and reverse directions to confirm proper conduction.
Open or Short-Circuit Test
| Terminal | Tester (+) | Tester (–) | Normal Resistance | Remarks |
|---|---|---|---|---|
| + | – | N1 | 360 kΩ ± 20% | Normal |
| – | + | P | 720 kΩ ± 20% | Normal |
| L1 | L2 | Control Box | ∞ Ω | No continuity expected |
| L1 | N2 | – | 1.01 MΩ / 761 kΩ | Within reference |
| L2 | N2 | – | 1.65 MΩ / 1.14 MΩ | Within reference |
| P | N1 | – | 360 kΩ ± 20% | Normal |
⚠ If any reading is 0 Ω or significantly deviates from reference, replace the Active Filter Module.
Diode Test (D1)
| Terminal | Tester (+) | Tester (–) | Expected Reading |
|---|---|---|---|
| L2 | P | 1.32 MΩ / 663 kΩ | |
| P | L2 | 1.01 MΩ / 762 kΩ |
Measurements vary slightly depending on multimeter type (FLUKE 11 or SANWA PM3).
Check Point 2: Output DC Voltage (Between P and N1)
Procedure
Measure DC voltage between P and N1 terminals under two conditions:
Compressor stopped
Compressor operating
Compare readings:
Voltage during operation must not drop below the value when the compressor is stopped.
⚠ If the operating voltage is lower than the stopped voltage, the Active Filter Module is defective and must be replaced.
Summary Table
| Test Item | Terminal(s) | Expected Value | Judgment / Action |
|---|---|---|---|
| Open / Short Circuit | (+) ↔ N1 | 360 kΩ ± 20% | Replace AFM if 0 Ω / ∞ Ω |
| Diode Test | L2 ↔ P | ~1 MΩ (bidirectional) | Replace if abnormal |
| Output Voltage | P ↔ N1 | Stable / increases during operation | Replace if drops under load |
