My DFPlayer Mini module arrived from China as it did not produced any sound on the output. I'm getting tired lately with the quality problems of cheep modules, so this time I did not asked for refund, instead was suspecting a soldering problem. And I was right.
I also measured the current draw [1:56], and discovered the speaker polarity [2:25].
Online documentation:
https://www.dfrobot.com/wiki/index.ph...