mcmurdo NAV-7 is a GMDSS Tri-channel NAVTEX Receiver designed to provide up to date weather and marine safety information to commercial vessels. It meets IMO requirements and is designed for simplicity of operation. Here is some information about it's capabilities:
- Receives on all three international NAVTEX frequencies (490 kHz, 518 kHz, 4209.5 kHz)
- Can be set up to filter out unwanted stations and/or message categories
- Capable of being connected to an Integrated Bridge System (IBS), transferring NAVTEX messages to other navigational aids
- Will accept UTC time & date information from the IBS port if available
mcmurdo NAV-7 is a GMDSS Tri-channel NAVTEX Receiver designed to provide up to date weather and marine safety information to commercial vessels. It meets IMO requirements and is designed for simplicity of operation. Here is some information about it's capabilities:
- Receives on all three international NAVTEX frequencies (490 kHz, 518 kHz, 4209.5 kHz)
- Can be set up to filter out unwanted stations and/or message categories
- Capable of being connected to an Integrated Bridge System (IBS), transferring NAVTEX messages to other navigational aids
- Will accept UTC time & date information from the IBS port if available
Commercial in Confidence 35-506 Iss 1
NAV-7 Service Manual Page 1
Table of Contents
1. Introduction ..........................................................................................................3
1.1. Scope..............................................................................................................4
1.2. Applicability .....................................................................................................4
1.3. Servicing equipment .......................................................................................4
1.4. Safety notices .................................................................................................5
2. Assessment ..........................................................................................................7
2.1. Maintenance tasks..........................................................................................7
2.2. Routine testing ................................................................................................7
2.3. Assessment ....................................................................................................8
3. Maintenance procedures...................................................................................10
3.1. Inspection......................................................................................................10
3.2. Functional test...............................................................................................10
3.3. Disassembly..................................................................................................12
3.4. Reassembly ..................................................................................................18
3.5. Leak Testing .................................................................................................20
3.6. Factory Reset................................................................................................21
3.7. Receiver Set up ............................................................................................21
3.8. Software Download.......................................................................................22
4. Fault finding........................................................................................................23
4.1. NAVTEX Update — Optimising Reception...................................................23
4.2. Fault location.................................................................................................24
4.3. Service Bulletin 08 ........................................................................................25
5. Repair procedures .............................................................................................27
6. Spares .................................................................................................................28
Appendix 1 : Specification .......................................................................................29
This document is McMurdo Limited copyright (©) and contains proprietary owned intellectual property rights and
confidential data. All rights are strictly reserved. The information must not be used except for the agreed purpose.
Unauthorised use, reproduction or issue to any third party is not permitted without the prior written authority of
McMurdo Limited. This document is to be returned to McMurdo Limited when the agreed purpose is fulfilled.
Commercial in Confidence 35-506 Iss 1
NAV-7 Service Manual Page 3
1. INTRODUCTION
NAVTEX is a method of transmitting navigational warnings and weather forecasts
from designated coast radio stations. All English language transmissions are
made on 518 kHz. Each station is allocated several time ‘slots’ during the day,
when it is permitted to transmit; these are normally at four hourly intervals. The
only exceptions to this are gale warnings and search and rescue messages,
which may be transmitted at any time.
Reception of NAVTEX is normally limited to an area of 200 - 300 miles radius
around each transmitting station, although considerably greater ranges are
possible at night.
Subject to IMO approval, additional local language transmissions may be made
on 490 kHz and on 4209.5 kHz.
The NAV-7 has been designed to the latest European and International
specifications to provide up to date weather and marine safety information to
commercial vessels. It meets IMO requirements under GMDSS and is designed
for simplicity of operation. It will display reliable information day after day within
designated NAVTEX coverage areas.
Installation is straightforward. Connect the NAV-7 to a 12 or 24 volt DC supply
and connect a suitable antenna. Switch it on, and it will start displaying and
storing NAVTEX messages without further manual intervention. Note that if there
are only a couple of NAVTEX stations within range it may be several hours before
the first message is received.
If you are within an area where you are able to receive from many NAVTEX
stations (particularly at night), the NAV-7 may overwhelm you with information. It
can therefore be set up to display only those stations and message categories
you want to receive and which are applicable to the area in which you are sailing.
Normally, routine messages are repeated at four hourly intervals. Provided that
the NAV-7 is left running, repeated messages are not displayed more than once.
Each message is retained for three days (72 hours) after its last reception before
being automatically deleted, unless the message has been marked as locked.
Permanent installation of the NAV-7 can be made with either the bulkhead-
mounting bracket or the flush panel mounting kit provided.
The NAV-7 has been designed to meet the requirements of IMO MSC.148 (77)
and IEC 61097-6 (Ed 2.0).
The NAV-7 contains 3 receiver channels, one each tuned to 490 kHz, 518 kHz
and 4209.5 kHz. The NAV-7 will receive on all 3 frequencies simultaneously in
those parts of the world where transmissions are available (refer to Appendix I
and to the McMurdo website at www.mcmurdo.co.uk for latest information).
Commercial in confidence 35-506 Iss 1
NAV-7 service manual Page 4
The NAV-7 can be setup to filter out stations and/or message categories that are not
required by the User.
The NAV-7 is capable of being connected to an Integrated Bridge System (IBS),
transferring NAVTEX messages to other navigational aids if required. Note that the
IBS must be compliant with the serial port requirements of IEC61097-6 (Ed 2.0).
The NAV-7 will accept UTC time & date information from the IBS port if available.
UTC time & date will be used to timestamp received NAVTEX messages.
1.1. Scope
This manual provides the instructions to enable routine and emergency servicing of
the NAVTEX equipment listed below. This manual represents the original equipment
manufacturer’s (OEM) service documentation applicable to these products.
1.2. Applicability
This manual applies to the following NAVTEX equipment:
• McMurdo NAV-7 Part number 35-850-001
1.3. Servicing equipment
The following tools and equipment is required to carry out the servicing detailed in
this procedure.
Equipment:
Active antenna (ACT-1)
Power supply (12-24V)
Handtools:
Calibrated torque driver (40-50cNm) with attachments:
5mm A/F socket
Small cross-headed screwdriver
Antistatic precautions
The electronics section of the NAV-7 is sensitive to electrostatic discharge (ESD)
which can cause immediate or hidden long term damage. It is important that the PCB
is only handled under suitable antistatic conditions.
Ideally, a fully grounded workstation, which has conductive
surfaces to avoid the build up of static charge, should be
used.
As a minimum, the operator must be connected to a good
earth point through a resistance of 1Mohm. This is usually
achieved by wearing a suitable wrist strap.
Commercial in Confidence 35-506 Iss 1
NAV-7 Service Manual Page 5
1.4. Safety notices
Please read the following information for your safety:
This product has been assessed as presenting negligible hazard in a sealed
serviceable state.
Safety analysis
The following table summarises the nature of the hazard which may be present when
the unit is opened or serviced; each hazard is discussed at greater length in the
detailed sections.
Hazard cause Hazard identification Precautions
High Voltage Risk of shock Handle appropriately, avoid
contact
General precautions for chemical agents (adhesives,
greases, IPA)
Observe all safety precautions relevant to the country of operation. As
a general rule, protective overalls, gloves and goggles should be worn
when handling these chemical agents, but different countries may have additional
requirements which must be observed.
Ensure that all chemical agents are handled in accordance with the manufacturer's
instructions, and that suitable protective clothing is worn.
Make sure that the working area is well ventilated, and that chemical substances are
not left exposed. Observe good hygiene practices; do not eat, drink or smoke when
handling chemicals.
Read the manufacturer's instructions before using any chemical agent.
Wear goggles Wear overalls Wash hands Wear gloves
Commercial in Confidence 35-506 Iss 1
NAV-7 Service Manual Page 7
2. ASSESSMENT
2.1. Maintenance tasks
Service providers are reminded that it is their responsibility to ensure that the
procedures herein are followed, that only McMurdo approved parts are fitted, and that
good practice is observed.
The functions which can be performed by service providers are:
• Routine testing
• Software download
• System set up
• Fault diagnosis
• Repair
2.2. Routine testing
NAV-7 has automatic Built In Test Equipment (BITE).
BITE runs all the time in the back ground and monitors for correct operation of the
receiver sub systems including the monitoring of antenna supply current.
In the event of an error being detected;
A fault indication icon may be displayed on screen
Front panel LED may flash (according to menu set up option)
Buzzer may sound (according to menu set up option)
Detail of the alarm event is displayed under the Alarm mode, current alarms
page.
Alarm events are sent over the data interface output port(s) using the ALR
sentence format.
Whatever the reason for the return the NAV-7 must be subjected to a full
assessment before any other action is taken. The agent has a responsibility to
ensure the NAV-7 is completely serviceable and is fit for its purpose.
Included in the user handbook are full details on:
• Installation
• Set up
• Operation
Therefore these items are not repeated in this manual.
Commercial in confidence 35-506 Iss 1
NAV-7 service manual Page 8
2.3. Assessment
Every NAV-7 returned for servicing, of whatever nature, must be fully assessed to
determine its operational status.
Assessment form
The assessment form, shown on the next page, is an essential tool in performing
diagnosis. It may be used to support customer billing and must accompany any
warranty return to the manufacturer.
Commercial in Confidence 35-506 Iss 1
NAV-7 Service Manual Page 9
NAV-7 ASSESSMENT CC Date
Customer Address
Type Serial No
Antenna type: Vessel name:
Customer comments
Return to Customer? Warranty
claim YES/NO
INSPECTION/DIAGNOSIS
Items Returned
Main unit
Antenna/bracket
Power cable
Manual
Item Condition
Software version:________________________
Diagnosis/Comments
FUNCTIONAL TEST
ATE (in factory only)
Burn-in
Functional Test
Comments
Conclusions
Assessed by Signed Date
New Parts Fitted
RF PCB
Keypad
LCB screen
Display PCB
Gasket
Backbox
Pass Fail
Commercial in confidence 35-506 Iss 1
NAV-7 service manual Page 10
3. MAINTENANCE PROCEDURES
3.1. Inspection
The NAV-7 should be inspected prior to any servicing/repair work.
The following should be inspected:
• Case – ensure no cracks in the plastic or other damage.
• Screen – Inspect display if possible to ensure not damaged.
• Rear connectors – ensure pins are straight and connectors are in good
condition.
• Key pad - Check operation.
3.2. Functional test
It is recommended that the unit is set up with an active antenna and tested to ensure
that messages are received on all channels and decoded correctly.
Alternatively a PC can be set up with a signal generator to test the receivers.
Please see the following page.
An external GPS input is required to test the NMEA port
The following should be checked:
• Check receiver operates OK on all 3 channels
• Check basic controls
• Check LCD contrast and brightness – ensure LCD temp does not exceed 70C
• Check time and date
• Ensure NMEA and other data ports operate correctly
On the following page is an example of a test setup which can be used to simulate
NAVTEX messages (example is for 518KHz).
Caution: 12VDC will be present on antenna connector in active mode. This should
not be connected to external test equipment.
Commercial in confidence 35-506 Iss 1
NAV-7 service manual Page 12
3.3. Disassembly
Warning: the backlight for the display is powered by 250V AC.
A clean room may be required when replacing the screen.
Back Box removal
1. Remove the 6 off self tapping screws
2. Lift off the back box and disconnect the ribbon cable.
Commercial in Confidence 35-506 Iss 1
NAV-7 Service Manual Page 13
RF PCB Removal
1. Remove the 3 off screws from the PCB. Note that the one screw may be
secured into a pillar and so will be of a different type.
2. Remove the 4 off connector clamps (see above) using 5mm socket or nut
runner.
Connector clamps
Commercial in Confidence 35-506 Iss 1
NAV-7 Service Manual Page 17
Removal of Display/Screen
NOTE: This should only be done in clean conditions – any dust or dirt will be
attracted to the screen and will show when powered up.
1. Remove the keypad – this lifts out.
2. Remove the 4 off screws retaining the display.
3. The display can now be lifted out.
The fascia/window assembly is supplied complete – if it is damaged please order
a replacement assembly.
Commercial in confidence 35-506 Iss 1
NAV-7 service manual Page 18
3.4. Reassembly
Reassemble fascia/display
1. Remove protective film from inside of screen before fitting display.
2. Place display on to fascia and secure 4 off screws and washers to
50cNm.
3. Fit ribbon cable to display. Ensure that the insulated side is away
from the PCB.
4. Fit the keypad and press home securely. Ensure that the top of the
pillars are level with the top of the keypad.
Refit Display PCB
1. Replace PCB on top fascia and reconnect the ribbon connector –
ensure the locking mechanism is secure.
2. Reconnect the backlight.
3. Refit 2 off screws to 50cNm as per below:
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mcmurdo NAV-7 is a GMDSS Tri-channel NAVTEX Receiver designed to provide up to date weather and marine safety information to commercial vessels. It meets IMO requirements and is designed for simplicity of operation. Here is some information about it's capabilities:
- Receives on all three international NAVTEX frequencies (490 kHz, 518 kHz, 4209.5 kHz)
- Can be set up to filter out unwanted stations and/or message categories
- Capable of being connected to an Integrated Bridge System (IBS), transferring NAVTEX messages to other navigational aids
- Will accept UTC time & date information from the IBS port if available
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