To post photos you need to have made 15 posts. It's our caveman way of insuring that you're not a spammer. We used to get a lot of spam; now we don't.
'Failed doohickey' can mean many things. Usually they just break and sit there, not doing their job. That lets the chain get loose, so it sounds like a trashing, slappy, rushing sound coming from the left side of the engine. That's the same sound that a properly functioning system makes when it simply needs adjustment.
If the broken bits get loose and tangled up in moving engine parts the sound can be anything from 'crunch-blam-tinkle-quiet' to Total Global Thermonuclear War. Obviously, having bits get loose and tangled up is a bad thing. In truth, that's less common than just sitting there not doing the job.
Here's a video that describes the balancer system:
There is a set of four videos, about 45 minutes in total, that goes over how to change out the part(s). If you're interested in that it can be found on the same channel or I can give you a link if you like.
It is possible to find some peace of mind by removing the left side cover and peering into left side to see if the doohickey is functioning properly. If you're interested in that, it can be described.