Janome 344 Service Manual

The Janome 344 is a high-performance sewing machine designed for both home and professional use. This service manual provides comprehensive technical information for maintenance, troubleshooting, and repair procedures. The machine features advanced stitching capabilities, automatic needle threading, multiple stitch patterns, built-in buttonholer, and durable construction. Below are key sections covering safety precautions, technical specifications, maintenance procedures, troubleshooting, and repair instructions.

1. Safety Precautions 2. Technical Specifications 3. Machine Overview 4. Maintenance Procedures 5. Disassembly Instructions 6. Electrical System 7. Timing Adjustment 8. Troubleshooting Guide 9. Parts List 10. Reassembly Procedures

Safety Precautions

Before performing any service procedures, ensure proper safety measures are followed to prevent injury and equipment damage.

Precaution	Description
Power Disconnection	Always unplug machine from power source before servicing
Grounding	Ensure proper grounding to prevent electrical shock
Sharp Components	Handle needles and cutting tools with care
Moving Parts	Keep hands clear of moving mechanisms during operation
Cleaning Safety	Use approved cleaning solvents only in well-ventilated areas
Lubrication	Use only recommended lubricants in specified quantities

Technical Specifications

Model: Janome 344
Stitch Types: 34 built-in stitches including utility, decorative, and stretch
Stitch Length: 0-4mm adjustable
Stitch Width: 0-5mm adjustable
Max Sewing Speed: 820 stitches per minute
Needle System: HAx1 SP
Presser Foot: 9mm lift
Motor: 70W DC motor
Power Supply: 110-120V, 60Hz
Weight: 15.4 lbs (7 kg)

Machine Overview

Key components and their functions for proper identification during service procedures.

Component	Function
Handwheel	Manual control of needle position
Stitch Selector	Choose from 34 built-in stitch patterns
Feed Dogs	Control fabric movement during sewing
Tension Assembly	Regulate upper thread tension
Bobbin Case	Hold and tension lower thread
Needle Bar	Hold needle and control vertical movement
Hook Assembly	Form stitches with needle and bobbin thread

Maintenance Procedures

Regular maintenance ensures optimal performance and extends machine lifespan.

Daily Cleaning: Remove lint and dust from bobbin area and feed dogs
Weekly Oil: Apply 1-2 drops of sewing machine oil to designated points
Monthly Inspection: Check needle condition, belt tension, and electrical connections
Quarterly Service: Complete disassembly for thorough cleaning and lubrication

WARNING! Use only Janome-approved lubricants and cleaning solutions.

Disassembly Instructions

Step-by-step procedures for accessing internal components.

Remove top cover by loosening 4 Phillips screws
Detach front cover by releasing 2 snap clips
Remove needle plate using flat-head screwdriver
Extract bobbin case and shuttle hook assembly
Disconnect motor wiring harness from control board
Remove handwheel and main shaft assembly

CAUTION! Document screw locations and keep small parts organized.

Electrical System

Electrical components and testing procedures.

Component	Test Procedure	Specification
Main Motor	Measure resistance between terminals	15-25 ohms
Foot Controller	Check variable resistance	0-5k ohms progressive
Power Cord	Continuity test	No breaks or shorts
Control Board	Voltage output test	5V DC regulated

Timing Adjustment

Proper timing ensures smooth operation and quality stitches.

Rotate handwheel to bring needle to highest position
Check hook point alignment with needle eye
Adjust hook assembly position if necessary
Verify needle-to-hook clearance (0.05-0.1mm)
Test stitch formation with scrap fabric

Note: Use timing gauge tool JN-344-TG for precise adjustment.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Thread breaking	Incorrect tension, burred needle	Adjust tension, replace needle
Skip stitches	Timing off, bent needle	Adjust timing, replace needle
Machine jams	Thread jam, lint buildup	Clear jam, clean bobbin area
Motor not running	Power issue, faulty foot control	Check power source, test foot control
Uneven stitches	Feed dog issue, tension problem	Clean feed dogs, balance tension

Parts List

Essential replacement parts with reference numbers.

Needle: Part #JNM-344-N (HAx1 SP system)
Bobbin Case: Part #JNM-344-BC
Drive Belt: Part #JNM-344-DB
Motor Brushes: Part #JNM-344-MB
Light Bulb: Part #JNM-344-LB (12V 5W)
Foot Controller: Part #JNM-344-FC

Reassembly Procedures

Reverse disassembly steps with attention to proper alignment and torque specifications.

Install main shaft and handwheel assembly
Reconnect motor wiring harness
Install hook assembly and bobbin case
Replace needle plate and front covers
Secure top cover with 4 Phillips screws
Test all functions before returning to customer

Final Check: Verify smooth operation, proper stitch formation, and electrical safety.