This app was mentioned in 5 comments, with an average of 2.00 upvotes
There's an app I like to use, Stereo Test. I'm guessing there's something similar for an iPhone -- if not, there's a hole in their catalog.
If I use this app set to alternating on full volume mine turns back on.
https://play.google.com/store/apps/details?id=com.jasonfarrell.stereotest
Personally, I use the Stereo Test app. Only takes 296 kB, which is a bit smaller than your YouTube download.
If I use this app set to alternating on full volume mine turns back on.
https://play.google.com/store/apps/details?id=com.jasonfarrell.stereotest
Use this app, set to alternate and 100% volume. I have no clue why it helps, but it does. https://play.google.com/store/apps/details?id=com.jasonfarrell.stereotest