Repair knowledge
maintenance
trouble shooting [
1
] [ 2 ]
Upper thread defective incomplete
Probable causes
Actions
Thread take-up spring incomplete contact
Securely couple connectors
Tension base connector incomplete contact
Securely couple connectors
Upper thread breakage timing contact incomplete
Clean and adjust the upper thread breakage timing contact
Deformed design
Probable causes
Actions
Frame drive belt is too tight
Loosen
Frame guide rails are clogged with foreign materials
Clean the rails
Frame drive circuit defective
Replace
Memory plate defective
Replace
Overall weight of the frame is excessive
Decrease R, P. M
