Identify what the supply controls
Keysight’s training distinguishes constant-voltage and constant-current operation. The active mode depends on the settings and connected load. Seeing CC or CV is therefore an observation about the supply’s operating condition, not a diagnosis of a particular phone component.
Use a supported training load
Ask an instructor to demonstrate the mode change using approved equipment and a suitable demonstration load. Record set values, displayed values and mode. Do not connect an unfamiliar device, battery or board merely to see which indicator lights up.
Avoid universal current signatures
A current pattern needs context: device state, connection method, timing and model information. A screenshot of a supply display cannot establish a complete fault diagnosis. Keep the manufacturer’s limits and qualified procedure central. Progress means explaining the mode and the test question, not memorising one voltage setting for every repair.
The supply changes from CV to CC
Ask the instructor to explain the mode in the approved demonstration setup. The indicator alone does not name a failed component. Record settings and load context before attempting any interpretation, and do not transfer the setup to a customer board.
Your practice record
- Set values versus displayed values
- Active operating mode
- Authorized demonstration load
- No generic injection recipe
Sources and further reading
Manufacturer and technical references for the checks discussed in this guide. Follow the instructions for your exact device and equipment.
Repair procedures involve heat, electricity, fragile parts and customer data. Practise under qualified supervision and work only on devices you are authorized to service.
