Thanks! Mine doesn't have that extra tension dial but it does have the bar that you loop thread through for tighter or less tension. I will play around with threading through that differently then the manual says. I don't know why sewing machine manuals are written to be so useless for the most part.

Definitely lose one of the holes on the bar. I think mine has 4 and I only use maybe 2. Depends on my thread.

How long have you had your machine? If you've had it awhile and never serviced, you can also take your tension apart (remember how it came off thought) and run your tension discs on fine sandpaper. Gets them nice and clean.

I know you probably already did this, but someone else might not have, a good cleaning could help in case there is a "blob" of fuzz or thread stuck in there.

I have the Brother 1500. I have taken it apart to clean it as it's straight stitch and easy to maintain. I oil it at least once a week when I'm sewing a lot. I haven't taken out the tension discs though. I have flossed it a few times with waxed dental floss :D
I saw a machine repairman do this so I do it every now and then. Thanks again for your help.

If there is alot of wax, that could be part of the problem. it could be getting sticky and your thread may not like it. The only thing we ever used was "thread dip" Been awhile can't remember what it really was. I know it wasn't waxy, but boy it could work magic when it was hot and humid out.

You machine repairman may have been using unwaxed dental floss. Since you've already used the waxed dental floss, there may be some wax gumming up the tension path. You may want to try and remove it with unwaxed floss.

I meant to type no waxed dental floss. I have gotten a few thread balls come out of the disc with the floss. I guess it needs a good professional cleaning but no shop for miles around.