Mitsubishi PLK-E0504, Technical Manual

Page: 43 / 52

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