Bad Sewing Condition & Its Cause And Remedy - Mitsubishi PLK-E1010 Technical Manual

9. BAD SEWING CONDITION & ITS CAUSE AND REMEDY
Please fix the troubles during the sewing machine operation with referring to the
[NOTE]
following instructions.
Beside, if the trouble conditions are not coming under these classification, please
contact the sewing machine dealers nearby.
Bad condition
Tight upper thread tension
Strong thread take up spring
Upper thread is thicker than
Damages on shuttle hook or
1.
Upper thread
breakage
Damages inside presser foot
often happens
Needle touches with presser
Needle and shuttle hook are
Thread melts with needle heat
Thread tension discs are not
Thread take up spring swings
Upper thread is broken before
Needle size is bigger than
2.
Upper thread
is pulled out
from needle
Thread guide is in wrong
Needle and shuttle hook are in
Trimmer timing is not correct
Too short bobbin thread by
bobbin spinning at trimming
Bobbin thread tension is too
3.
Skip stitch
happens at
start sewing
Thread tail from needle is very
From the library of Superior Sewing Machine & Supply LLC • www.supsew.com
Cause
Poor thread quality
needle size
driver
needle hole
foot needle hole
not in proper timing
opened at trimming
too much
regular trimming
thread size
Pre-tension is too tight
position
bad timing
tight
short after trimming
Remedy
Use better quality thread
Adjust thread tension
Adjust thread take up spring
properly
Change needle to suitable size
Change them new ones or grind
them with buffing wheel or grind
stone
Change it new one or grind it with
buffing wheel
Move presser foot position
Adjust the timing
Slow down sewing speed
Use silicon oil
Use needle cooler
Adjust thread tension release
Adjust thread take up spring's
swing stroke
Adjust fixed knife and needle plate
position
Change needle to suitable size
Adjust pre-tension
Adjust thread guide position
properly
Adjust the position properly
Adjust trimmer cam position
Adjust movable knife position
Adjust synchronizer position
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
― 37 ―
Ref. page
& Item
----
6-3
7-14
----
----
----
7-6-1(6)
7-2
6-2(4)
----
----
7-17
7-14
7-12
----
7-16
7-5
7-2
7-10
7-11
7-18
----
6-3(1)
7-16
7-10
7-18
7-13
Control
unit
7-5