DURKOPP ADLER 906 Operating Instructions Manual page 131

Troubleshooting
12.2.3 Errors in sewing process
Error
Unthreading at seam
beginning
Thread breaking
Missing stitches
Operating Instructions 906 - 02.0 - 11/2016
Possible causes
Needle thread tension is too
firm
Needle thread and hook
thread have not been
threaded correctly
Needle is bent or sharp-
edged
Needle is not inserted
correctly into the needle bar
The thread used is
unsuitable
Thread tensions are too tight
for the thread used
Thread-guiding parts, such
as thread tube, thread guide
or thread take-up disk, are
sharp-edged
Throat plate, hook or spread
have been damaged by the
needle
Needle thread and hook
thread have not been
threaded correctly
Needle is blunt or bent
Needle is not inserted
correctly into the needle bar
The needle thickness used
is unsuitable
The reel stand is installed
incorrectly
Thread tensions are too tight Check thread tensions
Throat plate, hook or spread
have been damaged by the
needle
Remedial action
Check needle thread tension
 p. 27
Check threading path
 p. 25
Replace the needle  p. 24
Insert the needle correctly into the
needle bar  p. 24
Use recommended thread
 p. 131
Check thread tensions  p. 32
Check threading path
Have parts reworked by qualified
specialists
Check threading path
Replace the needle  p. 24
Insert the needle correctly into the
needle bar  p. 24
Use recommended needle
thickness  p. 131
Check the assembly of the reel
stand  p. 107
Have parts reworked by qualified
specialists
129