FURUNO MF-22A-4 Analog Display Unit: Marine Speed Indication, Technical Specifications, Troubleshooting and Spare Parts

Marine Analog Instrumentation | Ship Speed Indication | Replacement Equipment | Technical Support

Product Information

Manufacturer: FURUNO ELECTRIC CO., LTD.

Country of Origin: Japan, as marked on the identification plate.

Exact Model / Type: MF-22A-4

Product Name: Analog Display Unit

Instrument Category: Marine analog speed indicator

Display Unit: Circular, graduated analog dial

Visible Scale: Knots (KTS), including AHEAD and AST markings

Input Voltage: AC 100 V

Input Frequency: 50/60 Hz

Mounting Style: Flush mount, identified in the model's technical documentation

Reference Serial Number: 699-1662

Commercial Availability: Subject to current stock, inspection and condition verification.

Identification note: The serial number above belongs to the unit shown in the uploaded photograph. Confirm it against the physical nameplate before ordering replacement parts or requesting technical support.

Product Introduction

The FURUNO MF-22A-4 Analog Display Unit is a marine instrumentation component designed to present operational information through a traditional mechanical pointer and graduated scale. The photographed unit has a circular dial, a visible knots scale, and markings for AHEAD and AST.

Analog indicators remain useful on vessels where operators need to read information directly from a physical instrument without relying exclusively on a digital screen. A clear pointer, familiar scale and dedicated instrument face can help officers monitor operating information during routine vessel operations.

For marine engineers, electrical officers, technical superintendents and purchasing managers, identifying the correct model is essential when arranging maintenance or replacement. The MF-22A-4 model designation, electrical input rating, physical mounting arrangement and dial configuration should all be checked before procurement.

SM MARINE SERVICE™ supports marine equipment sourcing and enquiries for replacement instruments and spare parts, subject to availability and compatibility verification.

What Is the FURUNO MF-22A-4 Analog Display Unit?

The MF-22A-4 is an analog display instrument intended for marine measurement and indication applications. Its dial provides a visual reading through a moving pointer positioned against printed graduations.

The front panel identifies the display in knots. Technical documentation for this model identifies it as an analog indicator with a nominal indication range of −10 to +30 knots, a diameter of approximately 200 mm, and a flush-mount configuration. The photographed instrument's dial markings should be checked against the applicable system documentation before installation.

A display instrument must be distinguished from the equipment that measures or calculates the underlying value. Depending on the vessel's installation, the indicator may receive an electrical signal from a separate measurement or processing system. The exact signal characteristics and wiring arrangement must be confirmed from the relevant system documentation.

The MF-22A-4 should therefore not be treated as a complete independent speed-measuring system without confirming its intended system configuration.

Main Features

1. Analog pointer display

The instrument uses a mechanical pointer and printed scale, allowing the indicated value to be read visually.

2. Knots indication

The dial is marked KTS, the standard abbreviation for knots. The photographed scale includes markings associated with forward and astern indications.

3. Flush-mount installation

The model is identified in technical documentation as a flush-mount analog indicator. Confirm the mounting cut-out, securing arrangement and available installation space before ordering a replacement.

4. Clearly identified electrical input

The rear nameplate identifies an input of AC 100 V, 50/60 Hz. The replacement unit must match the vessel's electrical arrangement and approved installation requirements.

5. Marine equipment application

The model is listed in technical documentation for marine display-system applications. Confirm the exact parent system and interface before connecting the instrument.

6. Replaceable equipment sourcing

Where a matching unit is available, replacing a faulty indicator may be an option. The replacement decision should be based on model identity, interface compatibility, mounting dimensions and electrical requirements rather than appearance alone.

Main Technical Specifications

Parameter

Specification

Manufacturer

FURUNO ELECTRIC CO., LTD.

Model

MF-22A-4

Product type

Analog display unit / analog indicator

Indicated measurement

Speed indication in knots

Documented nominal range

−10 to +30 knots

Approximate instrument diameter

200 mm

Mounting style

Flush mount

Nameplate input

AC 100 V

Nameplate frequency

50/60 Hz

Country of origin

Japan

Serial number shown

699-1662

Important technical limitation: The indication range and approximate diameter are based on model-specific technical documentation. Confirm actual dimensions, installation clearances and signal characteristics against the applicable manual and the unit in hand. The serial number identifies the photographed example, not every MF-22A-4 unit.

Do not assume that the AC 100 V rating describes the signal input from the parent measurement system. Power supply and measurement-signal connections serve different purposes and must be verified separately.

Main Components and Their Functions

The photographs show the external instrument and its identification plate. The following describes the principal visible or functional elements without assuming an unverified internal circuit design.

1. Dial and graduated scale

The dial provides the visual reference for reading the indicated speed. Its markings must remain legible, and any replacement face or instrument should have the correct scale.

2. Pointer mechanism

The pointer indicates the measured or received value. Sticking, excessive friction, pointer misalignment or failure to move can make readings unreliable.

3. Instrument housing and mounting flange

The housing protects the internal mechanism. The outer flange and securing points hold the instrument in its intended mounting position.

4. Electrical connection system

The instrument requires the correct power and signal connections for the intended installation. Connector details and terminal assignments must be established from the approved wiring documentation.

5. Identification plate

The rear plate provides the model, input rating, serial number and manufacturer information. Keep this information available when requesting service, parts or a replacement unit.

Marine Applications

The MF-22A-4 is a marine analog indicator. Its documented speed scale and model references associate it with shipboard speed-indication arrangements. The exact installation on an individual vessel must be confirmed from its system drawings and equipment records.

Potential contexts for an appropriately configured indicator include:

Shipboard speed indication systems.

Marine measurement and monitoring installations.

Instrument panels requiring a flush-mounted analog display.

Replacement projects involving an existing MF-22A-4 installation.

Maintenance and refurbishment of older marine instrumentation.

The instrument should not automatically be described as a radar, echo sounder, GPS receiver, AIS unit or independent speed sensor. These are different equipment categories.

Before procurement, confirm which system supplies the speed signal and whether the existing indicator's scale, input, mounting and interface match the intended application.

Common Problems and Troubleshooting

The following are general diagnostic possibilities for analog marine indicators. They are not a verified list of model-specific failure codes or documented defects.

1. No pointer movement

Possible causes:

Loss of the required power supply.

Missing or incorrect input signal.

Loose or damaged wiring.

A fault in the instrument's internal mechanism.

A problem with the upstream measurement or processing equipment.

Recommended checks:

Review the vessel's approved electrical drawings.

Have a qualified marine electrician verify the supply and signal at the appropriate test points.

Inspect accessible wiring and connectors for looseness, corrosion or damage.

Determine whether the parent system is producing a valid output.

Arrange qualified instrument testing if the supply and signal are confirmed but the pointer remains inactive.

Do not open the housing or perform live electrical tests without appropriate qualifications and safety procedures.

2. Incorrect or unstable readings

Possible causes:

An incorrect or unstable input signal.

Wiring faults or poor electrical connections.

A problem in the upstream measurement system.

Mechanical friction or pointer damage.

An incompatible replacement instrument.

Recommended checks:

Compare the indication with an independent, approved reference where available.

Check the signal and wiring against the manufacturer's documentation.

Inspect the mounting arrangement for damage or distortion.

Verify the exact model and scale before replacing the unit.

Do not adjust the pointer or alter calibration without an approved procedure.

3. Intermittent operation

Possible causes:

Loose terminals or connectors.

Corrosion in the electrical connection path.

Intermittent power or signal supply.

Internal component deterioration.

Recommended checks:
Inspect accessible connections with the equipment safely isolated, review any recorded symptoms and arrange professional testing if the fault persists.

4. Display remains at zero

A zero indication does not, by itself, prove that the display unit has failed. The actual measured value may be zero, or the instrument may not be receiving the correct signal.

Check the upstream equipment, signal path, wiring and instrument response before concluding that the indicator requires replacement.

5. No illumination or poor visibility

The photographed dial is primarily a printed analog face. Any illumination or dimming feature must be verified for the installed configuration rather than assumed to be present in every unit.

Inspect the vessel's approved lighting or dimmer arrangement, if fitted, and consult the relevant documentation.

6. Electrical supply fault

The nameplate specifies AC 100 V, 50/60 Hz. A supply outside the permitted specification may cause malfunction or damage.

Verify the rated supply and wiring arrangement before energizing the unit. Never apply a different voltage simply because another marine instrument uses it.

Alarm and fault codes: No verified MF-22A-4-specific alarm-code list has been established for this article. Do not assign invented alarm messages or error codes to this analog indicator.

Maintenance Tips

Appropriate maintenance helps preserve instrument readability and reliability.

Keep the dial and protective window clean using a method suitable for the materials.

Check for cracks, condensation, corrosion and physical damage.

Inspect the housing, mounting flange and accessible fasteners.

Check external wiring and connectors for signs of deterioration.

Verify the reading against an approved reference during scheduled maintenance when required by the vessel's procedures.

Record the model, serial number, observed symptoms and any maintenance performed.

Follow the vessel's maintenance schedule and applicable technical documentation.

Avoid abrasive cleaning products, unapproved solvents and adjustments to the pointer mechanism. Do not remove the rear cover unless the approved service procedure and appropriate personnel permit it.

The warning label on the photographed unit specifically cautions against opening the cover because hazardous electrical voltages may be present and there are no user-serviceable parts inside.

Spare Parts & Replacement Availability

SM MARINE SERVICE™ can assist with enquiries for the FURUNO MF-22A-4 Analog Display Unit and related marine instrumentation, subject to stock and technical verification.

Potential sourcing requirements include:

Complete MF-22A-4 analog display unit.

Matching replacement indicator.

Compatible mounting and securing hardware.

Approved wiring and connector components.

Internal electronic or mechanical parts, where separately available and technically confirmed.

Associated display-system components, where required for the specific installation.

The items above are possible sourcing categories, not confirmation that every component is separately replaceable or currently in stock. Exact component part numbers should be taken from the applicable parts list or confirmed by the manufacturer.

New, Used, Refurbished and Reconditioned Units

Depending on availability, SM MARINE SERVICE™ can assist with enquiries for:

New equipment.

Used equipment.

Refurbished equipment.

Reconditioned equipment.

Tested working equipment.

Condition and testing status must be confirmed for the specific unit offered. A used instrument should not be described as tested or operational unless appropriate testing has actually been completed.

Information to Include in a Spare Parts Enquiry

For a faster and more accurate quotation, provide:

Model: MF-22A-4.

Clear photographs of the front and rear identification plate.

Serial number, if available.

Nameplate voltage and frequency.

Existing system model and vessel application.

A description of the fault or replacement requirement.

Required quantity and destination country.

These details help reduce the risk of ordering an instrument with the wrong electrical rating, mounting arrangement or signal interface.

Why Ships Still Use Analog Display Equipment

Analog indicators remain relevant in some marine installations because they offer a direct, familiar visual indication. Operators can read the pointer position quickly, while a dedicated dial can be integrated into an existing instrument panel.

For older vessels, retaining a compatible analog indicator may also reduce the scope of a maintenance project compared with redesigning an entire display system. However, compatibility, equipment condition, spare-part availability and applicable vessel requirements must be assessed before deciding to repair or replace an existing instrument.

A suitable replacement must match the required function, electrical input, signal characteristics, scale and mounting arrangement. Similar appearance alone is not sufficient evidence of compatibility.

Frequently Asked Questions

What is the FURUNO MF-22A-4?

The MF-22A-4 is an analog display unit with a circular dial marked in knots. Technical documentation identifies it as a flush-mount analog indicator with a nominal range of −10 to +30 knots.

Who manufactures the MF-22A-4?

The identification plate states FURUNO ELECTRIC CO., LTD.

What is the country of origin of the MF-22A-4?

The photographed identification plate states “MADE IN JAPAN.”

What is the input voltage of the MF-22A-4?

The visible nameplate specifies AC 100 V, 50/60 Hz. Verify the actual unit's nameplate before connecting it.

What is the measurement range of the MF-22A-4?

The model's technical documentation identifies a nominal range of −10 to +30 knots. Confirm the dial configuration and applicable documentation before installation.

Is the MF-22A-4 still available?

Availability depends on current stock and sourcing conditions. Contact SM MARINE SERVICE™ with the model number and photographs to enquire about a suitable unit.

Where can I buy the FURUNO MF-22A-4?

You can enquire with SM MARINE SERVICE™ about sourcing the exact model, subject to availability and verification of the required specification.

Are MF-22A-4 spare parts available?

Availability depends on the component, production status and compatibility requirements. Provide the model, serial number and a description of the required part for assessment.

Can I buy a used or refurbished MF-22A-4?

Used, refurbished or reconditioned equipment may be available through sourcing, depending on stock. The specific unit's condition and test status should be confirmed before purchase.

What can cause an MF-22A-4 to stop indicating speed?

Potential causes include an interrupted supply, missing signal, wiring problems, an upstream system fault or a defect within the instrument. Diagnosis should follow the approved wiring documentation.

Can another analog indicator replace the MF-22A-4?

Not necessarily. Check the indication range, input and signal characteristics, mounting dimensions, electrical requirements and parent-system compatibility before approving a replacement.

Where can I download the MF-22A-4 manual?

Consult the applicable manufacturer documentation for the instrument and its parent system. Technical documentation may list the MF-22A-4 in equipment drawings or outline-drawing sections. Confirm that any manual you obtain applies to the actual installation.

Can SM MARINE SERVICE™ supply the MF-22A-4 internationally?

SM MARINE SERVICE™ accepts marine equipment sourcing enquiries for international requirements. Availability, condition, shipping arrangements and delivery destination must be confirmed for each order.

Short Product Description

The FURUNO MF-22A-4 Analog Display Unit is a flush-mount marine analog indicator featuring a circular knots scale and AHEAD/AST markings. The photographed unit is marked AC 100 V, 50/60 Hz and identifies FURUNO ELECTRIC CO., LTD. as its manufacturer. Technical documentation identifies a nominal indication range of −10 to +30 knots and an approximate 200 mm diameter. Contact SM MARINE SERVICE™ for enquiries about replacement equipment, spare parts and worldwide marine equipment sourcing, subject to availability and compatibility verification.

User Manual & Technical Resources

The following documentation types are relevant when researching or servicing the MF-22A-4. A model-specific direct PDF download has not been verified for every category, so no unverified download address is provided.

Product / Operator Manual

Consult the applicable operating documentation for the parent marine measurement system. Confirm that the instrument is covered by the selected manual.

Installation Manual

Use the correct system installation documentation to verify the mounting arrangement, supply requirements, signal interface and wiring.

Service / Maintenance Manual

Use approved service information for diagnostic procedures, internal repairs and any permitted adjustments. The instrument's warning label cautions against opening the cover.

Outline Drawings / Technical Specifications

The model is listed in technical documentation as a flush-mount analog indicator, with a nominal range of −10 to +30 knots and an approximate 200 mm diameter. Confirm dimensions and installation details from the applicable drawing before ordering.

Technical Documentation Checklist

Before using any manual or drawing, confirm:

The MF-22A-4 model designation.

The applicable parent-system model.

The correct electrical input rating.

The signal and terminal configuration.

The mounting dimensions.

The revision and applicability of the document.

SM MARINE SERVICE™

Marine Automation & Navigation Equipment Supplier

Available Condition:
• New Equipment • Used Equipment • Refurbished Equipment • Reconditioned Equipment

Stock Location:
• Bangladesh • China

Services:
• Worldwide Shipping • Technical Support • Spare Parts Supply • Marine Equipment Sourcing

Contact Information
SM MARINE SERVICE™ Samir Market, DT Road, Pahartali, beside CDA Market, Chattogram, Bangladesh
Mobile / WhatsApp / Viber: +88 01818 929292
Email: info@smmarineservice.com
Website: www.smmarineservice.com

-

+

Buy Now