Understanding the teaches timeless lessons in isolated power supply design: current-mode control, optocoupler feedback, soft-start, and transformer-coupled feedback. Moreover, it empowers you to repair rather than scrap expensive equipment. By studying the external circuit, you can diagnose faults, design a modern substitute, or even build your own high-performance DC-DC converter.
Unregulated DC (18V) ----+---[100µF]---(Pin1 VCC) |---[0.1µF]---(Pin2 GND) Pin3 RC ---[100k]---+---[100pF]--- Pin4 CT +---[1nF]--- GND Rm1-2316 Schematic
Optocoupler (e.g., CNY17) collector ---(Pin6 FB) Optocoupler emitter --- GND Understanding the teaches timeless lessons in isolated power
Look for the input voltage (usually labeled "Vcc Unreg" or "+18V_unreg") and all output voltages (+5V, +15V, -15V, +24V). These labels tell you the converter’s goal. Unregulated DC (18V) ----+---[100µF]---(Pin1 VCC) |---[0
Find the capacitor on Pin 8 (soft-start) and the series RC network between Pin 5 and Pin 6 or Pin 5 and GND. If these are damaged, the supply will oscillate or fail to start. 6. Common Failures & Troubleshooting Based on the Schematic From field reports, the Rm1-2316 itself is robust but the external components fail. Using the schematic, you can diagnose: