General Assist Technical Reference
ACTPM Testing
Active Filter Module resistance checks
Power-off test procedure for checking the ACTPM (Active Filter Module)
The ACTPM can be checked using resistance measurements with the unit isolated from power. Use the terminal combinations and expected values below as the reference for testing.
Electrical safety: Perform these checks with power OFF. Isolate the equipment, confirm the supply is de-energised and disconnect all control harnesses before carrying out resistance tests.
1. Before testing
- Switch power to the system OFF.
- Confirm the circuit is electrically isolated before accessing the PCB.
- Disconnect all control harnesses during the power-off tests.
- Set the multimeter to Auto Range - Resistance (Ω).
- Inspect the ACTPM for visible or physical damage before measuring resistance.
Important: A short circuit within the ACTPM can trip the power supply circuit breaker.
2. ACTPM terminal identification
The test points shown in the source information are identified as:
| Terminal | Identification |
|---|---|
| - | Negative terminal |
| + | Positive terminal |
| L1 | L1 terminal |
| L2 | L2 terminal |
| N1 | N1 terminal |
| P | P terminal |
3. Expected resistance values
Connect the meter leads exactly as shown below. Resistance readings are nominal reference values from the ACTPM test information.
| Black Lead | Red Lead | Expected Value |
|---|---|---|
| - | + | 360 kΩ |
| - | L1 | 360 kΩ |
| - | L2 | Over 1 MΩ |
| - | N | 0 Ω |
| + | P | 720 kΩ to 900 kΩ |
| N1 | P | 360 kΩ to 540 kΩ |
Check the terminal marking on the ACTPM: The source table identifies one measurement as black lead - to red lead N, while the pictured lower terminal is labelled N1. Use the marking on the specific module being tested and the applicable model service information where terminal naming differs.
4. Test procedure
| 1 | Isolate power. Confirm the system is de-energised before accessing the ACTPM. |
| 2 | Disconnect control harnesses. All control harnesses must be disconnected for the power-off resistance tests. |
| 3 | Inspect the PCB. Check for visible signs of physical damage, overheating or component failure. |
| 4 | Set the multimeter. Use Auto Range resistance (Ω). |
| 5 | Measure each terminal combination. Observe black/red lead polarity and compare the readings with the table above. |
| 6 | Assess the result. If readings are outside the listed reference values or physical damage is present, follow the applicable model service procedure before returning the unit to service. |
5. Quick reference
Test condition: Power OFF
Meter mode: Resistance (Ω), Auto Range
Harnesses: Disconnect all control harnesses
Visual inspection: Check PCB for physical damage
Known symptom: An ACTPM short can trip the power supply circuit breaker
Meter mode: Resistance (Ω), Auto Range
Harnesses: Disconnect all control harnesses
Visual inspection: Check PCB for physical damage
Known symptom: An ACTPM short can trip the power supply circuit breaker
Technical reference for trained service personnel. Always use the applicable model service documentation where model-specific values or terminal designations differ.