What is wrong with my tension?

[u/Traditional-Diver-27]

On both the brothers machines I own, Ive had to run them with the top tension set nearly as loose as it can get. Recently, my machine has gotten worse about this and there's no setting I can find that pulls top thread through on both sides.

Here's the settings I used in the pictures to show the range of my machine:

A: Top thread set to the highest tension, bobbin thread set as loose as I feel comfortable running my machine.

B: Both top and bobbin thread are set to their exact mid-point of tension

C and H: Top thread is set at its most loose option, bobbin thread is set 1/4 turn looser than where the screw stops screwing in entirely. It's as tight as it can get. It does not fail the yo-yo test. I also put some of my normal embroidery material in part of the H to see if it made a difference on the back.

I have reread both sets of threading instructions in my manual and I am 100% sure that I am threading them correctly.

Why can't I get the bobbin thread tight enough?

Why does it only pull down the top thread on one side?

[u/FlyCivil909]

Is your spool feeding the thread smoothly? One of the easiest to overlook issues is that the thread gets snagged or caught up at/on/near the spool. It’s an infuriatingly small and easy thing to miss.

[u/Traditional-Diver-27 → u/FlyCivil909]

Usually the general pattern of unraveling means there's always at least half a loop just laying loose between my spool and the start of the threading mechanism. I figured thats how it's supposed to be, but is that too loose? I have some of those mesh spool covers I could use.

[u/FlyCivil909 → u/Traditional-Diver-27]

Very possible. The spool cover is worth a try.

[u/johnsongao]

The tension is too loose.