Lambda EMS‑40‑25‑1‑D is a high‑power, 40 V/25 A switch‑mode DC power supply from TDK‑Lambda used in laboratory test and burn‑in rigs, offering programmable voltage/current output via analog or RSTL digital interface. Common failure modes for this model include overheating of the internal MOSFET array (often due to inadequate heat sinking), failure of the main transformer winding, and degradation of the output filter capacitors under high ripple conditions; these can manifest as sudden shutdowns, output droop, or audible noise. First‑check diagnostics: verify that the input AC is within spec and the unit’s fan/heat sink are clean and operational; inspect the output voltage/current with a calibrated multimeter while monitoring for ripple spikes; examine the main transformer and MOSFET heatsink for burn marks or excessive temperature rise.[oss-gpt-20b]