A friend has a Brother PE100---an older low-tech embroidery machine that she inherited---I have helped her get started in embroidery. I received a call that the needle will NOT pick up the thread-----we do not know why---taken emb card out-turned off-turned on-new needle--inserted properly---taken bobbin case out and put back in---I have been machine embroidering for about 10 years using Brother machines----I cannot figure out WHY it suddenly will not pick up the thread----suggested trying unwaxed dental to clean upper thread path or winding a NEW bobbin---I need suggestions from other CUTIES----please---all ideas are welcome----I have found SOOOO much help from everyone here---God bless you.
Usual reasons for not picking up the bobbin thread are that the needle is in backwards (backwards needles don't pick up bobbin threads reliably, and skip stitches), or the needle isn't correctly seated in the needle clamp, or the machine is a little bit out of time.
If you are feeling like fixing it yourself (I would only consider this on my very old regular machine) You could check the link. It may also show you what to look for to see if it needs repair.
http://sewusa.com/Sewing_Machine_Repair/Sewing%20Machine%20Hook%20Timing.htm
Bless you for helping your friend!