Read the data plate first
Same brand, different model, different problem. The label tells you what you're actually working on.
The short version
- Snap a photo of the data tag before you test anything. Model, serial and any suffix in one shot.
- Make sure the manual or wiring diagram you pull up is for that exact model.
- Suffixes matter. A "-B" or a new serial range can mean a different board or different codes.
- Fault codes are model-specific. Look them up for the unit in front of you.
Shop tip
Photo every data tag when the rig comes in. Parts, warranty and the next tech all need it, and your phone already has it.
Try it on a service call
Put the lesson to work on a hands-on troubleshooting case.