Made of high-quality ABS and copper materials, more durable 1. Ensure the board under test is powered off and all electrolytic capacitors on the motherboard are fully discharged before testing. Never test while the motherboard is powered on. 2. Identify PIN1 of the optocoupler (marked with a small dot on the test board and labeled “1”). 3. Connect the optocoupler test board to a USB power source. Use the test probe to make contact with the optocoupler. A flashing indicator light confirms the optocoupler is functional (light intensity may vary between units; flashing alone indicates functionality). 4. Ensure firm and stable contact between the test board and the optocoupler during measurement. 5. If the indicator light remains constantly on or off, remove the optocoupler from the circuit board and retest by inserting it into the breadboard socket. 6. Designed specifically for 4-pin through-hole and surface-mount optocouplers. Not compatible with other optocoupler types. Specifications: Part Name: Optocoupler Tester Generation: 6th Generation Features: USB-C interface, power-on indicator light, supports 4-pin plug-in and SMD optocoupler testing, built-in flashlight, rechargeable battery Color: Green Material: ABS + Copper Package Contents: 1 × Optocoupler Tester 6 × Copper Probes Note: Color appearance may vary slightly due to lighting and screen settings. Measurement tolerance: ±1–3 cm.