Sorensen PTM15-3.5 power supply Repair Service

The Sorensen PTM15‑3.5 is a 105–125 V AC input, 14.2–15.8 V DC output, 3.5 A switched‑mode power supply commonly used to feed industrial drives or control boards. Typical failure modes include input overvoltage damage to the rectifier bridge, output voltage sag due to capacitor degradation, and fuse or MOSFET burnout from overload or short‑circuit conditions; these often manifest as a loss of regulated DC output or audible fan noise. Begin troubleshooting by verifying the AC supply with a multimeter, checking the main input fuse and any intermediate fuses for continuity, then measuring the DC output voltage while the unit is powered on to confirm regulation within spec. If the output is out of range, inspect the output filter capacitors for bulging or leakage and test the switching MOSFETs for shorts; finally review any error codes displayed on the control panel for clues to a specific fault.