rinchan314

I recently inherited a 1992 Viking 400 from my mother. She says she recently had it serviced, but otherwise it has been sitting in her closet for over a decade. I first started using it about a week ago, piecing together my next project (because what else does one do in quarantine?) and it seemed to be working fine. A couple days ago, though, I had a couple issues.

First, I had my fabric get stuck down beneath the plate--like, really stuck, to the point where I couldn't get the needle up, and I was so worried I'd broken something. When the needle it got stuck it made a loud, jarring noise and vibrated until I stopped trying to sew. I managed to get everything unstuck, cleaned out the bobbin area, gave it a try, and, apart from a slight tension issue that was easily fixed, everything seemed fine.

A little while later that same day, I was winding a bobbin. It was my first time trying to wind one while the thread was in the needle. Usually I pull the thread out, but the instruction manual said it was okay, so I thought I'd give it a try. Well, as I was doing that the needle snapped (so I won't be trying that again!) Once again, I cleaned the bobbin area as best I could before I tried any more sewing. I still have not found the needle tip, which slightly concerns me, but I don't see it anywhere beneath the plate, and since I imagine it snapped from the thread tension it probably went flying across the room. Again, after that problem everything seemed fine. I worked for a couple more hours, put everything up, and went to bed.

Then yesterday I went to sew some more, and when I turned on the machine it did something strange. Right as soon as I turned it on, it made a kind of whirring, jarring sound, very short, only a couple seconds long, similar to the noise it made when the needle got stuck the day before. While it made that noise, the needle automatically shifted a couple ticks to the left and re-centered itself. The noise it made when I turned the machine on is not like the noise it makes when I automatically shift the needle position. It never did this before yesterday, but it has since done it every time I've turned the machine on, no matter the amount of time the machine was off. Other than this noise, there is nothing strange about the machine. I have not used it overmuch since I noticed the noise, but as far as I can tell it is sewing normally and does not make any strange noises besides that brief sound when turning the machine on. The noise concerns me, though, and I cannot find anything online or in the instruction manual that might explain why it's suddenly doing this. I know it's a long shot, but does anyone happen to know what might be causing it? I am worried it means something is broken, but my local shop is closed for quarantine.

Things I have tried/checked already:
- I am 100% certain it did not make this noise before yesterday
- Both the bobbin and needle are threaded correctly
- Nothing visible trapped beneath the plate
- No dust or lint in the bobbin area or under the feed plate
- Feed dogs raise and lower and are working properly
- Needle is inserted correctly and is not bent or dulled
- The presser foot is attached correctly
- The machine is sewing correctly, and there are no noises while sewing or moving the components
- The tension seems fine
- There are no skipped stitches or birds nest tangles
- Changing functions, stitch choices, stitch length, etc. does not seem to help
- Changing thread does not seem to help
- Turning it off and on again and unplugging/re-plugging the machine does not help
- It makes the noise regardless of the position of the bobbin spindle, the presser foot, and the feed dogs
- It makes the noise regardless of whether the machine is fully threaded or the removable components completely disassembled

I am completely at a loss, and I give up. Does anyone have any idea what might be wrong?