A section found in many manuals of electrical devices or (in some cases) software manuals.
The section tells symptoms of common types of failures and supposedly helps the user to fix these problems, step by step.
However, in real failure situations, the troubleshooting guides are often completely useless - they only cover very, very simple cases of problems. Typically they have no solutions for really tricky problems, or even simple problems. (Sometimes I question the intelligence of whoever writes these guides, and the people who find these instructions absolutely enlightening. "Q: There's no picture! A: Make sure the cable is connected. Make sure power is turned on.")
The joys of "consumer electronics"...
I apologise if this writeup has typos. My monitor's troubleshooting guide didn't tell me what to do if the monitor thinks it's over the maximum refresh frequency (blank screen, rapidly flashing power light) even when the cable is not connected... The only display I have is my TV, and it's behind my back.