You can schedule basic training during service calls
Fair warning, there likely won't be any fun pictures with this one. Sorry :(
You can find this information by digging around on the site, but I figured it might be a good idea to post a little blurb with the same information: you can request some basic training and explanations during a service call. If you're working with tough materials on a regular basis and those are causing needles to break or timing to go just slightly off, I can walk you through the process of checking what can be done by a beginner to see what might be causing the issue.
Having a background in machinery repair isn't necessary to do basic fiddling on most sewing machines. You can check the state of your equipment just by looking, feeling, or listening to what's going on with your machine. Some of the most common issues with light duty industrial or home machines are that you might have put some material through that the machine wasn't rated for, or only handles gingerly.
Sewing over sequins or beads, leather, vinyl, denim, etc. can overtax a lot of lighter duty machines, and it will usually show by the needle bending and hitting the needle plate. This could cause the middle portion of the needle plate to bend and get barbs that catch thread and throw off the lower thread's ability to be caught, or might cut the upper thread during sewing. This is a quick diagnosis, but pretty easy to repair. You should almost always have a spare needle plate for those just-in-case moments if you're a professional/regular stitcher.
This is one of many possible issues that could arise, and generally one of the most visibly obvious ones. The on-site training I offer is $50 for roughly 30-45 minutes where you can ask questions or have me show you how to work on your machine in-shop or at home. I can also walk you through the steps I follow when adjusting the machine for any work it needs.
Your sewing machine guy:
I am a Jack-of-Most-Trades that was roped into working on sewing machines, and managed to find a knack for it. I love hilarity, fixing things that are broken, video games, dogs, cats, most other creatures, and sleep. Especially sleep. On here you'll usually find tidbits about recent visits or ADORABLE CREATURES THAT LOVE ON ME WHILE I WORK. There may be ancient machines, there may be unique machines.