Service manual

ManualsBrandsmcmurdo ManualsMusical equipmentNAV-7

Commercial

in

confidence

SMARTFIND

NAVTEX

service

manual

Page

20

3.5.

Leak

Testing

The

SMARTFIND

NAVTEX

is

not

a

sealed

unit.

Therefore

there

is

no

requirement

to

leak

test

the

product.

However

if

the

unit

is

flush

mounted

then

the

front

fascia

is

approved

to

IEC60945-4

for

protected

equipment.

3.6.

Factory

Reset

In

set

up

mode

there

is

an

option

for

FACTORY

RESET.

This

should

be

used

with

caution.

This

will

return

all

user

configurable

settings

to

the

factory

default

–

including

resetting

the

two

serial

port

parameters

to

default

settings.

It

will

not

reset

the

receiver

PCB

DAC

settings

(see

3.7

below).

It

will

not

delete

NAVTEX

messages.

3.7.

Receiver

alignment

–

checking

only

DAC

settings

are

not

serviceable

in

the

field

because

special

production

test

equipment

is

required

to

correctly

calibrate

the

receiver

alignment.

If

after

review

the

DAC

settings

you

suspect

that

they

are

not

correct

contact

McMurdo

Ltd

customer

service

for

advice.

Review

of

DAC

settings

The

DAC

settings

are

preset

at

PCB

manufacture.

The

DAC

settings

are

stored

in

the

EEPROM

located

on

the

SMARTFIND

GMDSS

NAVTEX

RF

PCB.

The

settings

are

accessible

via

the

service

panel

as

follows:

H

Switch

on

SMARTFIND

GMDSS

NAVTEX

and

wait

for

the

start

up

screen

to

disappear.

H

Press

and

hold

the

ENTER

key

H

Using

the

soft

keys

select

VIEW

RECEIVER

OPTIONS

H

Then

VIEW

SYSTEM

OPTIONS

H

Then

RECEIVER

SETUP

H

You

will

then

be

prompted

for

a

password

H

Press

and

release

the

ENTER

key

and

enter

the

word

SERVICE.

H

When

complete

select

DONE

on

the

keyboard

H

Then

select

VERIFY

PASSWORD.

This

will

display

the

service

screen

which

will

include

the

DAC

settings.

View

the

figures

for

the

518kHz

receiver,

490kHz

receiver,

4209.5kHz

receiver,

the

AGC

reading

and

the

RSSI

setting.

The

518,

490

and

4209.5

kHz

figures

are

the

settings

for

the

three

VCO’s.

The

AGC

(Automatic

Gain

Control)

is

the

figure

used

to

set

the

bias

voltage

input

to

the

AGC

circuitry

and

thus

control

the

gain

of

the

LNA

located

on

the

RF

PCB,

RSSI

is

figure

used

to

calibrate

the

signal

strength

indicator

bar.

Typical

figures

for

these

parameters

are

shown

below.

518kHz:

141

AGC:

80