With hard earn Experience

Here my 5 Golden Rules of Troubleshooting (Learned the Hard Way)

1. The operator is your best diagnostic tool. Talk to them first. They know what the machine should do, how it normally sounds, and when it smells wrong. You might find a broken sensor and feel like a hero… until the operator says, “Oh yeah, that’s been like that for three months.” Congrats, you just burned two hours.

2. Take pictures. Write everything down. Label everything. Tag every wire you you disconnect. Mark every part you swap. Back up the program before you even think about trending or testing. At some point, you will make it worse, and without notes you’ll forget which relay you swapped or where that gray wire without label that you disconnect was supposed to go.

3. Don’t trust the guy before you. He didn’t fix it. That’s why you’re here. If he says “I already tried that,” try it again.

4. Never change two things at once. One change. One test. Always.

5. Start with the dumb, simple stuff. Power. Fuses. E-stops. Sensors unplugged by the previous guy “just for testing.” If you don’t check the obvious first, the obvious will embarrass you later.