Practical servicing — DC supply fault-finding: Does a typical DC power supply troubleshooting workflow proceed through four major stages (input/transformer, rectifier, filter, and regulator) to isolate faults systematically?

Introduction / Context:
Most textbook DC supplies, especially linear designs, are described in four functional blocks: transformer (or input stage), rectifier, filter, and regulator. A structured troubleshooting process mirrors these blocks, moving from the AC input toward the DC output to quickly localize issues such as blown fuses, failed diodes, dried capacitors, or faulty pass elements.

Given Data / Assumptions:

• We consider a common linear DC supply architecture.
• Safety practices (mains isolation, discharge procedures) are observed.
• Measurements are made with suitable instruments (DMM, scope).

Concept / Approach:
Diagnose block by block: verify primary input and transformer secondary; check the rectifier for correct polarity and ripple; confirm the smoothing filter reduces ripple to expected levels; verify the regulator produces a stable, correct DC output. This staged approach is both pedagogically common and practically effective. Although switch-mode supplies have different internal blocks, a staged approach remains valid conceptually (input EMI, PFC, primary switch, secondary rectification, post-regulation).

Step-by-Step Solution:

Verification / Alternative check:
Use an oscilloscope at each stage: absence of the expected waveform indicates the faulty block. For example, correct secondary AC but zero DC after rectifier implies a rectifier failure.

Why Other Options Are Wrong:
“Incorrect” ignores widely taught four-block models. Limitations tied to linear-only or specific rectifiers are unnecessary; the staged method generalizes conceptually even when internal implementations differ.

Common Pitfalls:
Skipping input checks; replacing parts without confirming the faulty block; ignoring ripple specifications that reveal filter issues.

Final Answer:
Correct