Janome 3434D Serger Parts Manual

The Janome 3434D is a professional-grade serger machine designed for high-speed overlocking and finishing seams. This parts manual provides comprehensive information about all components, replacement parts, maintenance procedures, and technical specifications for the 3434D model. Below are key sections covering parts identification, maintenance, troubleshooting, and ordering information.

1. Parts Identification 2. Needle System 3. Loopers and Threading 4. Feed Dog System 5. Tension Assembly 6. Cutting Mechanism 7. Motor and Drive System 8. Maintenance Schedule 9. Replacement Parts Ordering 10. Technical Specifications 11. Troubleshooting

Parts Identification

Key components: Upper looper, Lower looper, Needles, Feed dogs, Cutting blade, Tension dials, Stitch length dial, Differential feed dial.

Part Name	Description
Upper Looper	Forms upper thread loop for overlock stitch
Lower Looper	Forms lower thread loop for stitch formation
Needles	Standard 130/705H system needles
Feed Dogs	Dual feed system with differential control
Cutting Blade	Removable upper and lower blades
Tension Dials	Four-dial system for upper/lower loopers and needles
Stitch Length Dial	Adjusts stitch length from 1-4mm
Differential Feed Dial	Controls fabric feeding ratio (0.7-2.0)
Presser Foot	Standard serger foot with removable sole
Thread Guides	Color-coded threading system

Needle System

Uses standard 130/705H system needles. Maximum 2 needles.

Needle installation: Loosen needle clamp screw, insert needle with flat side to back.
Needle positioning: Ensure needles are at highest position before threading.
Replacement: Replace needles every 8-10 hours of sewing time.
Compatibility: Use only Janome 130/705H needles for optimal performance.

WARNING! Always disconnect power before changing needles. Use proper needle insertion tools.

Loopers and Threading

Upper and lower loopers require precise threading sequence.

Upper looper threading: Follow color-coded guides from spool to looper.
Lower looper threading: Ensure thread passes through all tension discs.
Threading sequence: Upper looper first, then lower looper, then needles.
Thread tension: Adjust dials for balanced stitch formation.

CAUTION! Do not force thread through loopers. Use tweezers for difficult threading.

Feed Dog System

Type: Dual feed system with differential control.
Stitch Length: Adjustable 1-4mm.
Differential Ratio: 0.7-2.0 for stretch and specialty fabrics.
Feed Dog Height: Adjustable for different fabric thicknesses.
Replacement: Feed dogs replaced as complete assembly only.
Maintenance: Clean feed dog area after each project.
Lubrication: Apply sewing machine oil monthly with heavy use.

Tension Assembly

Four tension dials control upper looper, lower looper, and two needles.

Standard Settings: Upper looper: 4-5, Lower looper: 4-5, Needles: 4-5.

Adjustment: Turn dial clockwise to increase tension, counterclockwise to decrease. Balance check: Test on scrap fabric before project. Maintenance: Clean tension discs weekly with compressed air. Replacement: Tension assemblies replaced as complete units.

Cutting Mechanism

Upper and lower cutting blades for fabric trimming.

Blade replacement: Remove presser foot and needle plate.
Upper blade: Loosen screw, slide out old blade, insert new.
Lower blade: Remove two screws, replace blade assembly.
Alignment: Ensure blades meet properly for clean cutting.

Tip: Replace blades when cutting becomes uneven or fabric pulls.

Motor and Drive System

110V AC motor with belt drive system.

Motor specifications: 110V, 60Hz, 0.8A.
Belt inspection: Check for cracks or stretching every 6 months.
Belt replacement: Remove side cover, loosen motor mount, replace belt.
Speed control: Electronic foot pedal with variable speed.
Maximum speed: 1300 stitches per minute.
Motor brushes: Replace when machine loses power or sparks.
Lubrication: Oil motor bearings annually with light machine oil.

WARNING! Disconnect power before servicing motor. Use certified replacement parts only.

Maintenance Schedule

Daily: Clean lint from bobbin area and feed dogs. Weekly: Oil moving parts. Monthly: Check belt tension and needle alignment.

Replacement Parts Ordering

Use genuine Janome parts only. Include model number (3434D) and part number when ordering.

CAUTION! Non-genuine parts may void warranty and cause machine damage.

Technical Specifications

Stitch types: 3/4 thread overlock, rolled hem, flatlock. Speed: 1300 SPM. Thread: Standard serger thread. Weight: 15.4 lbs. Dimensions: 13.4" x 11.8" x 12.6". Warranty: 25-year limited warranty.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Uneven stitches	Tension imbalance	Re-thread machine; adjust tension dials; check needle condition.
Thread breaking	Burred looper/tension	Inspect loopers for burrs; replace if damaged; adjust tension.
Fabric not feeding	Feed dog issues	Clean feed dogs; check differential feed setting; replace feed dogs if worn.
Machine jams	Thread buildup	Remove needle plate; clean all thread remnants; re-oil moving parts.
Poor cutting	Dull blades	Replace cutting blades; ensure proper blade alignment.

Service: Contact authorized Janome service center for major repairs.

Support: 1-800-631-0183; www.janome.com