Identify without disassembly
A readable exterior model label is useful. Removing covers or approaching unsafe hardware is not.
Separate control behavior
Wall control, remote and keypad symptoms can help explain what is and is not responding.
Keep previous work connected
Programming, sensor and prior service notes become more useful when they remain attached to the correct opener.
Let the visit confirm the cause
Model details support preparation, but they do not replace inspection or create a remote diagnosis.