Bernina 930 Sewing Machine Repair Manual

The Bernina 930 is a high-quality mechanical sewing machine known for its durability and precision stitching. This repair manual covers essential maintenance, troubleshooting, and repair procedures for the Bernina 930 model. Below are key sections for safety precautions, machine features, disassembly instructions, common issues, lubrication guidelines, and reassembly procedures.

1. Features and Specifications 2. Safety Precautions 3. Tools Required 4. Disassembly Instructions 5. Common Problems and Solutions 6. Lubrication and Maintenance 7. Electrical System Repair 8. Stitch Quality Issues 9. Reassembly Guidelines 10. Parts List and Ordering 11. Troubleshooting Guide

Features and Specifications

The Bernina 930 features a robust mechanical design with precision engineering for reliable performance.

Feature	Description
Stitch Types	Straight stitch, zigzag, decorative stitches
Stitch Length	Adjustable 0-4mm
Stitch Width	Adjustable 0-5mm
Bobbin System	Front-loading rotary bobbin
Feed Dog	Drop feed capability
Presser Foot	High-lift mechanism
Motor	DC motor with foot control
Weight	Approximately 22 lbs (10 kg)
Built-in Features	Built-in needle threader, reverse stitch
Power Requirements	110-120V AC, 60Hz

Safety Precautions

Always follow safety procedures when repairing sewing machines.

Disconnect power: Unplug machine before any repair work.
Remove needle: Always remove needle when working on bobbin area.
Use proper tools: Use sewing machine-specific tools to avoid damage.
Work in clean area: Ensure workspace is clean and well-lit.

WARNING! Electrical shock hazard - always unplug machine before servicing. Moving parts can cause injury.

Tools Required

Essential tools for Bernina 930 repair and maintenance.

Screwdrivers: Phillips #1, #2 and flathead assortment
Needle-nose pliers: For small parts handling
Tweezers: For bobbin and thread removal
Lubricating oil: Sewing machine specific oil
Cleaning brush: Small bristle brush for lint removal
Multimeter: For electrical testing
Allen wrenches: Various sizes for adjustment screws

CAUTION! Use proper tools to avoid stripping screws or damaging components.

Disassembly Instructions

Step 1: Remove needle, presser foot, and throat plate.
Step 2: Remove top cover screws and lift off housing.
Step 3: Document wire connections before disconnecting.
Step 4: Remove bobbin case and shuttle hook assembly.
Step 5: Remove handwheel and motor assembly if needed.
Step 6: Carefully remove stitch length and width control mechanisms.
Step 7: Keep screws organized by location for reassembly.

Common Problems and Solutions

Frequent issues encountered with Bernina 930 and their remedies.

Thread bunching: Check bobbin threading, tension settings, and needle condition.

Skip stitches: Replace needle, check needle bar timing, verify hook timing.

Motor not running: Check foot control, power cord, and motor brushes.

Uneven feeding: Clean feed dogs, check presser foot pressure, verify feed dog height.

Lubrication and Maintenance

Regular lubrication points and maintenance schedule.

Monthly: Oil hook race, needle bar, and presser foot bar.
Weekly: Clean lint from bobbin area and feed dogs.
Annual: Complete disassembly and thorough cleaning.
As needed: Replace motor brushes when worn to 1/4 inch.

Tip: Use only sewing machine oil - other oils can gum up mechanisms.

Electrical System Repair

Troubleshooting and repairing electrical components.

Test power cord: Check continuity with multimeter.
Foot control: Verify variable resistance operation.
Motor brushes: Inspect for wear and replace if necessary.
Light bulb: Replace with correct voltage bulb.
Wiring: Check for frayed or disconnected wires.

WARNING! Always unplug machine before electrical testing to prevent shock.

Stitch Quality Issues

Diagnosing and correcting stitch formation problems.

Problem	Possible Cause	Solution
Uneven stitches	Tension imbalance	Adjust upper and lower tension
Thread breaking	Burred needle or rough spots	Replace needle, polish thread path
Fabric puckering	Too much tension	Reduce tension, check needle size
Bird nesting	Incorrect bobbin threading	Rethread bobbin completely
Needle hitting	Timing issues	Adjust needle bar/hook timing

Reassembly Guidelines

Proper reassembly sequence for Bernina 930.

Install hook race and bobbin assembly first.
Reattach needle bar and check timing alignment.
Reconnect electrical wires following documentation.
Install top cover and handwheel.
Test operation without thread before final assembly.
Verify all adjustments before returning to service.

CAUTION! Test machine slowly after reassembly to detect any binding.

Parts List and Ordering

Common replacement parts for Bernina 930.

Needles: System 130/705 H
Bobbin Case: Part #01233230001
Motor Brushes: Part #01291420001
Drive Belt: Part #01291430001
Light Bulb: 15W screw base
Tension Assembly: Part #01291440001
Foot Control: Part #01291450001

Order parts from authorized Bernina dealers or certified suppliers.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Machine won't start	Power issue/foot control	Check power outlet, test foot control, inspect cord
Noisy operation	Lack of lubrication	Oil all moving parts, check for loose components
Thread breaks frequently	Rough spots/tension	Polish thread path, adjust tension, check needle
Fabric not feeding	Feed dog issues	Clean feed dogs, check height, verify not dropped
Inconsistent stitches	Timing/worn parts	Check hook timing, replace worn feed dogs

Professional Service: For complex issues, contact authorized Bernina service center.

Support: Bernina Technical Support: 1-800-405-2571; www.bernina.com