Take off the panel that conceals the lamp (see your instruction manual) and you will see another screw that needs to be removed before you can take the larger back panel off.
it is a needle thread tension problem
as the tension wheel makes no difference , that indicates that the thread is not between the tension plates but behind them
you can set or check the tension by simply pulling on the thread before you thread the needle
proper tension is when there is a resistance to pulling the thread by hand
Out of alignment means the timing is off...take it to a pro to have it cleaned and re-timed...if that's the real problem.
However, it seems that you think the issue is may be a bobbin holder that wasn't installed properly??
Do you have a top, side, or front loading bobbin?
Sorry...I don't understand: "If I manually turn the bobbin and holder clockwise just as the needle comes down, it goes all the way down without breaking or bending."
Do you mean that you're turning the hand wheel towards yourself...and that works properly? If so, it's probably not a timing issue.
If you have a metal bobbin case that you insert a wound bobbin into and then place that bobbin holder w/bobbin into your machine...perhaps the bobbin case just needs a slight turn in order to snap into place.
If that's not it, check your machine's manual to see what part might be missing...then, to find that small, shiny metal part, try shining a flashlight across the area where it was lost.
Most likely the timing needs to be adjusted. Try to do straight stitches on the left and then on the right. Does one skip but not the other? If so; get it timed.
Do you have a manual ? If not, Brother may well have one you can download, and there a many sites online that sell copies of manuals too.
Typically, it's not hard to get into a mechanical machine. There are usually just a few screws that have to be taken out to give access to most places inside. Look at the screws to see what kind of head is on them so you know which screwdriver bit you need.
A screwdriver or two is typically all you need - look at the screw heads to see what shape they are. If you don't have the right screwdriver, often you can get them with multiple styles of bits without it costing a great deal.
I don't have one of these machines specifically, but if the washer can't simply be lifted off, and you need to remove the back, there ought to be just a few screws to deal with.
I'm certainly not a sewing machine expert, but am very mechanical skilled and have maintained/repaired my family's machines years ago. i did some research and from what I can see, I don't believe the feed dogs on the XL-2230 are raiseable/lowerable via any control lever. They do, as most other machines, move/feed automatically by being actuated by a cam mechanism. I see no mention of any feed dog lever/button in the manual. In case you don't have the manual, I'll post a link for it below.
Have you taken off the footplate to look under the feed dogs to see if there is any balled thread or debris preventing them from raising? That might be the cause. If not, I also heard that the dogs are spring-loaded and will not raise until the machine or handwheel is rotated and the first stich is actually "caught". Have you tried sewing with it, or turning the handwheel? Just some thoughts and hope some of this helps.
http://www.brother-usa.com/VirData/Content/en-US%5CHAD%5CConsumer%5CUsersManual%5CUM_XL_2230_EN_205.PDF
I'll also include a video, but you can skip to near the end (about the 23 minute mark), where it shows the basic procedure for cleaning the feed dog area.
i have the same problem ,its the o ring on the inside of the machine on bobbin winder , i purchased the o ring from brother for 27 pence i just need to know if its safe for me to open the machine without lots of springs popping out xx
thanks i have purchased the washer from brother i just need to know is it safe to take the back off the machine and replace it my self the washer only cost 27 pence , if i take the back off will loads of springs pop out ha ha
clean bobbin area and rethread machine paying attention to top thread tension, ensure tensioner is functioning by slipping thread between plates at #0 pull fore and aft there should by slight resistance, wind to higher # and resistance should increase
