Brother HE-800C - Lower Thread Is Not Trimmed (Pulls When Material Is Removed); Feed Mechanism Does Not Operate or Motor Is out of Step

HE-800C
11. TROUBLESHOOTING
96
11-25. Lower thread is not trimmed (pulls when material is removed)
Items with a “*” in the “Page” column should only be handled by a qualified technician.
Cause Check Remedy Page
Fixed knife set Fixed knife and movable
knife do not mesh.
Adjust the fixed knife set installation position.
*
Knife tip is bent or chipped. Repair or replace the knife. *
11-26. Feed mechanism does not operate or motor is out of step
Items with a “*” in the “Page” column should only be handled by a qualified technician.
Cause Check Remedy Page
Feed motor Cord connection Check if there are any problems with the connection
and contacts of feed motor connector P22 on the main
P.C. board.
10*
Upper thread trimmer Upper thread trimmer
position
Remove and re-install the upper thread trimmer.
*
Check if the cam opens the
stop plate.
Adjust the cam position.
* If the feed mechanism operates when the cam has
not opened the stop plate, the cutter will bump
against the upper thread trimmer.
70*
Feed home position
sensor
Feed home position sensor
position
Adjust the feed home position sensor position.
*
Feed timing belt Feed timing belt tension Adjust the feed timing belt. *
4024Q
Fixed knife
Movable knife
Install so that the projection on
trimmer M is not inserted.
* Always make sure that the upper
thread trimmer is in the correct
position before use.
4018Q
4895M