International Power Sources PU40-10-1S Power Supply Repair Service

The International Power Sources PU40‑10‑1S is a 40 W, 7 V DC switching power supply rated at 5 A, commonly used in industrial control panels and servo drive enclosures. Common failure modes for this unit include output voltage sag due to degraded electrolytic capacitors on the rectifier or filter stages, transformer winding insulation breakdown leading to shorted secondary turns, and failure of the main switching regulator IC (often a MOSFET driver or controller). For troubleshooting, first verify that the input AC is within spec and measure the output DC voltage under no‑load and load conditions; then inspect the power board for obvious signs of overheating such as bulging capacitors, burnt traces, or discolored components. Finally, check the status LEDs (if present) and any diagnostic error codes supplied by the host controller to confirm whether the PSU is signaling a fault condition.