My brother pe770 is allowing bobbin thread to show on top sporadically which makes the stitching look like it is speckled with white. I have adjusted tension..cleaned and changed everything.

Try to loosen the bobbin tension a small amount and put your top tension at four. When you get a good stitch then you have the bobbin stitch set right. If you still can't get it set then it is probably the top tension spring that needs to be replaced.

Yes Adjust to more tight see what it'll do.
Bottom bobby is too tight or upper thread control is too lose.

Good luck

Mai

1. thread machine correctly.
2. make sure the bobbin is installed spinning the right way in the bobbin case.
3. put the tension knob back to middle (if this is possible numbered tension knob)

Hai Kim, Please change the correct size needle. Otherwise corrected the design in computer. For ex: stitches 12,702 decrease the design some 1000 or 2000 stitches.

Check your setting, you have your stitches set too far apart. Wherever on your machine you see the zigzag stich you will see other stich settings, look at it until you see the right amount of stiches you want.

Did you loosen the top thread?

here are some suggestions, if the suggestions don't help then the
machine needs to be checked to see if there is a adjustment or
timing problem
1. try changing the needle
2. try rethreading the machine top and bobbin
3. make sure the bobbin is turned the right way in the bobbin
case

have you tried to tighten the bobbin tension spring??

Besides the other advice here, check your bobbin case. At first I didn't get my thread hooked into the bobbin case properly and had problems that looked like the bobbin tension was not adjusted properly. I have to take the case out, put in the bobbin to make sure it's caught properly and then put it back into the machine. This is what worked for me.

First check threading. If it is done properly, then it's probably because it is dirty between the lower tension blade and the bobbin case body. Remove this blade, clean, reassemble and it shoud work.