A YouTube Channel I watch regularly. This is a good example of one of his typical videos. He is German, speaking in English, and it is a bit slow moving at times. I usually speed it up to 1.25 X normal speed. This is an excellent example of his methodical troubleshooting techniques to narrow down the problem – even on a modern type radio. No real special equipment used in this video. A multimeter is the main tool, but a signal generator is used, and a scope briefly, but really not necessary.
Maybe you might find it interesting.