Mitsubishi PLK-E0504 Technical Manual page 43

Bad condition
Too short bobbin thread by
bobbin spinning at trimming
Bobbin thread tension is too tight
3.
Skip stitch
happens at
start
Thread tail from needle is very
sewing
short after trimming
Pre-tension is too loose
4.
Trimmer timing is delayed
Thread tail from
needle is too
Upper thread tension release
long after
timing is too fast
trimming
Tread guide is in wrong position
Trimmer function is canceled
Fixed knife is dull
5.
Skip stitching happens at trimming Fix skip stitching
Trimming is not
Trimmer solenoid is out of order
functioned
Trimmer timing is wrong
Needle and shuttle hook
clearance is too big
Needle and shuttle hook timing is
not correct
6.
Needle is bent
Skip stitching
often happens
Needle is bent by driver
Needle is in wrong position
Presser foot position is not correct
Cause
－ －
38
Remedy
Use non racing spring with
bobbin
Loosen bobbin thread tension
spring
Decrease pre-tension
Adjust trimmer cam position
Adjust synchronizer position
Make thread take up swing
stroke smaller
Advance thread tension
release timing
Adjust thread guide position
properly
Adjust the position properly
Make pre-tension tighter
Adjust trimmer cam position
Adjust synchronizer position
Delay tension release timing
Adjust thread guide position
properly
Resume trimmer function
Change it new knife
Change trimmer solenoid
Adjust trimmer cam position
Adjust synchronizer position
Adjust needle and shuttle
hook timing properly
Adjust needle and shuttle
hook timing properly
Change it new needle
Adjust needle and diver
clearance properly
Amend needle position
Adjust needle and diver clearance
properly
Ref. page
& Item
----
6-3(1)
7-15
7-10
7-18
7-13
Control unit
7-5
7-2
7-15
7-10
7-18
Control unit
7-5
7-16
7-12
7-12
----
7-10
7-18
7-3
7-2
5-2
7-4
5-2
7-6-1