Record the visible state
Describe the lock symbol, sound and which controls respond. Use the matching model manual for ordinary unlocking instructions rather than an online sequence for another hob.
When the state persists
If the indicated lock clears but selections still fail, keep that distinction. Assessment can then focus on the actual control behaviour instead of treating every unresponsive hob as the same fault.
A useful distinction
A control that beeps while refusing a selection provides different evidence from a completely dead panel. Include both the sound and symbol, since the word locked alone may hide the actual behaviour.