I'd like to tell a quick story about successful troubleshooting.
A few months ago I rented a scissor lift to install lighting at my new office. When it arrived, the delivery person gave me a quick demo and off he went.
Well, when I went to actually use it - the lift went up by about a foot then stopped and screamed beeps of terror. It was broken!
But the display on the control read "18"
Rather than call the rental company, I searched "sinoboom fault code 18" to see what that meant.
I found a document that explained this meant there was a fault in the pothole protection board.
Not knowing what that was, I then searched for "pothole board sinoboom" and found that there are limit switches which detect that these little side-plates which swing out as the lift goes up have actually deployed. The board wasn't seeing that switch input.
So, I figured out where that switch was and discovered it was sticking. I exercised it a bit and the lift was fixed.