How to Find a Short Circuit with a Bench Power Supply

Before injecting voltage, confirm that the suspected rail really has an abnormal resistance and identify what components are connected to it. Injection is a localization technique, not the first measurement.

Identify the rail’s normal voltage

Use the schematic, regulator marking, datasheet or a known-good board. Never inject an arbitrary voltage into an unknown rail.

Choose conservative settings

Set a voltage that stays within the rail’s safe range and use a strict current limit. The goal is to create enough controlled power to reveal the fault without overstressing healthy components.

Look for where energy is dissipated

A shorted component may warm as current flows. Thermal imaging, careful temperature comparison or other appropriate methods can help identify the area.

Critical caution: Some low-voltage processor and memory rails can be damaged by voltages that seem small. Never use voltage injection unless you know the rail’s limits and topology.

Confirm the suspected component

Heat identifies where power is being dissipated, not necessarily the original cause. Isolate or measure the suspect device before replacing it.

SHORT-CIRCUIT WORKFLOW

Keep rail values and diagnostic decisions organized.

BoardIQ helps structure short-circuit diagnosis using resistance, reference and measurement data.

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