MARINE VHF RADIO

RU224A

Instruction Manual

Read this manual before using the equipment. Keep this manual with the equipment.

1. General Description 1.1 General

The RU224A is a VHF FM radiotelephone equipment equipped in ships for use in the international maritime mobile radiotelephone service allowing ship-to-ship and ship-to-shore VHF radio communications. Communication is possible to use the weather channels as a receive only, private channels other than ITU channels. Beside, this equipment has a built-in VHF DSC watch receiver, which is capable of continuous watch of ITU CH70.

1.2 Features

(1) Channel selection : Selection of International channels, USA channels, Private channels and Weather channels

(2) RF power changeover : 25 watts or 1 watt.

(3) Channel 16 automatic monitor function : If the handest is returned to the hanging position, it can monitor the channel 16 automatically.

(4) Dual watch function : It can monitor channel 16 while receiving other channels.

(5) Memory channels scanning function : Waves of maximum 10 waves can be memorized, and it can scan that channel.

(6) Continuous watch of ITU CH70 : By the built-in VHF DSC watch receiver, it is capable of continuous watch of ITU CH70. (When the power switch is turned on, it will auto- matically be in the watch state.)

(7) Digital selective calling function : * Prepare and display calling message * Display of when Distress call * Displays of when Distress, Urgency, Safety,

and Other call receiving * Automatic input of ship's position information * Self-checking function

(8) Dual power inputs : Operates under lOOVac of main power source or 24Vdc of the reserve source.

2. Composition

2.1 System Composition .

Fig 2.1 is standard composition of the equipment.

2.2 Equipment Composition

Table 2.1 is composition of the equipment.

3. Construction

The standard composition of the RU224A is as shown in Table 2.1. Depending on the use, options as shown in Table 2.1 are available. Table 3.1 is dimensions and mass.

Table 3.1 Dimensions and approximate mass.

Unit Dimensions (rnrn) I Mass 0%) 1

4. Specifications

4.1 MARINE VHF RADIO RU224A

4.1.1 General

(1) Frequency range

-Io RU224A VHF DSC RECEIVER

(2) Number of channels

(3) Communication system

(4) Emission

(5) Antenna impedance

(6) Supply voltage

(7) Audio input and output impedance

(8) Environmental conditions

H28O X W2 10 X Dl 30

(9) Dimensions

(10) Mass

< 6

Transmission 156.025 -- 159.500 MHz Reception 156.300 -- 159.500 MHz

160.625 -- 163.500 MHz

InternationallUSA VHF channels: 55 channels (CH 1-28 and 60-88 excluding CH75 and CH76) Private channels : Max. 10 channels Weather channels : Max. 10 channels

Simplex or semi-duplex press-to-talk system

F3E or F2B

50 ohms

1 OOV to 1 1 5Vac 50160Hz 1 $ and 24Vdc

600 ohms

Temperature - 1 5 "C to + 55 "C Humidity less than 95% (at 35%)

280 (H) X 210 (W) X 130 @) rnm

< 6kg

4.1.2 Transmitter

(1) RF power output 25 watts (High), 1 watt (Low)

(2) Oscillation system Frequency synthesizer system

(3) Maximum frequency deviation Within 31 5 kHz

(4) Occupied frequency bandwidth Within 16 kHz

(5) Frequency response 1 kHz reference, *3 dB on 6 dBloctave pre-emphasis between 300 Hz and 3000 Hz

(6) Signal to noise ratio More than 40 dB

(7) Modulation distortion factor Less than -20 dB at 1 kHz, 70% modulation

(8) Spurious radiation

(9) Frequency stability

4.1.3 Receiver

(1) Receiving system

(2) Intermediate frequency

(3) Sensitivity

(4) Receiving bandwidth

(5) Selectivity

(6) Signal to noise ratio

(7) Audio distortion factor

(8) Spurious response

(9) Local oscillation frequency stability

(1 0) Blocking

(1 1) Intermodulation

In band ; less than 2 . 5 ~ w (less than -69 dB)

Out of band ; less than 10 p w (less than -63 dB)

Within + 10 X 1 o - ~

Double superheterodyne

1st IF 48.5 MHz 2nd IF 455 kHz

Less than 2 p V (6 dB ,u ) for 20 dB noise quieting

More than 12 kHz for 6 dB down point

Less than 25 kHz for 70 dB bandwidth

More than 40 dB at 1 kHz, 70% modulation and 30 dB p RF input

Less than -20 dB at 1 kHz, 70% modulation and 30 dB ,u RF input

More than 80 dB

within + 10 X lom6

Interference signal voltage to produce the 20 dB noise quieting condition is more than 10 mV (80dB ,u ), when the interference signal separated more than 25 kHz from the desired signal is applied to RF input with the desired signal which is 6 dB greater than 20 dB noise quieting sensitivity level.

Noise suppression is less than 20 dB, when two interference signals of 1.78 mV (65dB p ) which are in the relation of inter-modulation are applied to RF input without the desired signal (Each inter-ference signal is separated mork than 25 kHz from the desired signal.)

(1 2) AF output

(1 3) Frequency response

4.1.4 DSC Function

Signal format and protocol

Modulation type

Modulating frequency

4.2 VHF DSC RECENER

(1) Received frequency

(2) Sensitivity

(3) Spurious response

(4) Blocking

(5) Intermodulation

More than 1 watt

1 kHz reference, rt3 dB on 6 dB/octave de-emphasis betweeh 300 Hz and 3000 Hz

: Conforms to CCIR Rec 493-6 and 541 -5

: F2BIG2B 1200 bps

: 1700 k 400 Hz

156.525 MHz

The character error rate is 1 % or less at 1 C( v of the receiver input voltage.

The character error rate is 1 % or less with the wanted signal 1.4 ,u V added with the unwanted signal 4.47mV.

The character error rate is 1 % or less when the wanted signal 1.4 ,u V added with the following unwanted signal.

unwanted signal

Input voltage 4.47mV Modulation 400Hz FM

deviation 3 kHz

The character error rate is 1 % or less when the wanted signal 1 . 4 , ~ V added with the following two unwanted signals.

unwanted unwanted signal 1 signal 2

Input voltage 2.5mV 2.5mV

Frequency separation from wanted signal 25 kHz 50 kHz

Modulation no MOD. 400Hz FM deviation 3 kHz

5. Operation

5.1 Operational Controls

Functions of Controls and Indicators

Anri tsu MARINE VHF RADIO RU224A

DISTRESS U OTHERS R T ITU USA P WX 1W I6WTH DW PS BS SHIFT

5.2 Function operating

Operation of Function Indication I Note

Selection of channels.

Selection of set contents.

CH Number + Indication of menu. [MENU] & Your station calls reduction files and discrimination memory of reduction other station. I DSC

Cancellation of channel number

1) Clearance of input number I DSC 2) You can return to before set item.

I

[SHIFT]

Registration of memory channels.

1) You decide input number and selection content, and can progress next step.

2) Practice of selected control contents. 1) You can stop called transmission. 2) You can stop the alarm.

[DISTRESS] Once the distress switch is set, distress signals is transmitted.

Once this switch is depressed, the RU224A is set at channel 16.

[DISTRESS DSC SENDING]

Once this switch is depressed, the RU224A is set at channel 70.

You can indicate memorized channel and selected contents by turns.

You can indicate memorized channel and selected contents opposite..

The channel of the RU224A is automatically released at CHI6 upon completion of telephone conversation when this switch is depressed.

Selection of low power output. (1W)

Pause scanning of memory channels.

Busy scanning of memory channels.

Selection of International channels.

Selection of USA channels. ~ - --

Selection of private channels

Selection of %ather channels

Operation of

key 21

22

23

1 2 6 1 [POWER] I Power onioff of the equipment.

Indication Function

24

25

I I LED I Function I Note I

Ndte

[DWl

[MI

[DMR]

[SQUELCH]

[VOLUME]

Practice of dual watch.

Registration and reference of memory channel.

changing of indicators brightness

Squelch control

Volume control

27

2 8

1 3 0 1 [OTHERS] I In case receiving of ordinary call, it lights.

29

DSC

I P ' I

[TI

[Rl

[SHIFT]+[8]

[SHIFT]+[9]

[SHIFT]+[Ol

During transmission.

During receiving.

[DISTRESS URGENCY1

If anybody wants to help you, this indication will light. DSC

Transmission and reception operation and function

1 I tem - - -

Setting channels KEY [SHIFT] & [4] : Selection of

International channels [SHIFT] & [5] : Selection of USA channels [SHIFT] & [6] : Selection of private channels [SHIFT] & [7] : Wather channels [Ol to 191 : Channel number [Cl : Cancel

. Indicator (LED)

mu1 : International channels [USA] : USA channels [PI : Private channels [WXI : Wather channels [XX] : Channel number

Setting the transmission output KEY : [SHIFT] & [I]

. Indicator (LED) : [l W]

Setting CH16 . K E Y : CH16

Setting CH70 . KEY : CH70

Initialization

International channel 16

OFF

Function and operation

1) Select the channel type using the [SHIFT] & [4],[5],[6], or [7] key.

The selected channel type is displayed. 2) When a 2-digit channel number which is stored is entered, the

channel is set and the channel number is displayed. When another number is entered, the indicator blinks and no channel is set.

3) When resetting the channel due an error, press the [C] key to clear the blinking display and repeat the entry described in 2) once again or enter 2-digit channel number once again.

4) When the clear or blinking status is continued for five seconds, the display is returned to the regular channel which is set immediately before.

1) When the [SHIFT] & [I] keys are pressed, the transmission output is reduced to 1 W.

2) When the [SHIFT'I & [I] keys are pressed once again, the transmission output is returned to 25W and the function is canceled.

3) When the function is in execution, the indicator is on.

1) When the [CHI61 key is pressed, the international channel CHI 6 is selected.

1) When the [CH70] key is pressed, the international channel CH70 is selected.

I tem

Setting Dual Watch KEY : [SHIFT'] & [8] Indicator (LED) : [DW

Setting CH 16 watch KEY : [I 6WTHI Indicator (LED) : [16WTH]

Setting dimmer KEY : [SHIFT] & [O]

- -

Initialization

OFF

Brightness "high"

Function and operation

1) If the [SHIFT] & [8] keys are pressed after CHX is set when the handset is in the on-hook state, both CHX and CHI6 are watched at intervals of 0.5 s.

2) When CHX input a signal, the reception status of CHX is held when the signal is effective and CH 16 is watched for 0.5 s at intervals of 5 s.

3) When CHX received no signal any more in 2), the dual watch starts in place of CHI6 5 seconds later . When CH16 inputs a signal in 2), CHI6 is held within 5 seconds after no more signal is received.

4) If the handset is picked up when a signal is inputted, the channel is set in CHI6 or CHX which receives another signal immediately before.

5) When the [SHIFT] & [8] keys are pressed once again or the [CHI61 key is pressed, the function is canceled and the radio is waiting state in CH16.

6) When the [DISTRESS] key is pressed, the function is canceled. 7) When the function is in execution, the indicator is on. 1) If the handset is changed from the off-hook state to the on-hook

state when the [SHIFT] & [CH 161 are held pressed, the channel is automatically changed to CHI 6.

2) Thereafter, CHI6 is held regardless of the'hook state until CHX is set.

3) When the [SHIFT] & [CHI61 are pressed once again, the function in canceled.

4) When the function is in execution, the indicator is on. 1) When the [SHIFT] & [0] keys are pressed, the brightness is

changed in the order of "high", "Medium", and "Low" successively . ("Low": Finely ad justable on a hardware basis)

Item

Reference to memory channels . KEY : [SHIFI'] & [9]

Indicator (LCD)

New registration and registration change of memory channels

Indicator (LCD)

Memory channel scan . KEY : [SHIFT] & [2]

Indicator (LED) : [PSI KEY : [SHIFT] & [3] Indicator (LED) : [BS]

Initialization

OFF

OFF

OFF

Function and operation

1) When the [SHIFT] & [9] keys are pressed, the memory channels list is displayed on the line on the LCD. Display example : Memory channel

0 : ITU 12 2) When there is no registered memory channel, the channel type and

number are not displayed. 3) The display line can be shifted by pressing the [ A] or [ V ] key. 4) When the [SHIFT] & [9] keys are pressed once again, the

function is canceled. 1) When the [ENTER] key is pressed in the state of 8.1), the state is

changed to the state of 8.2). 2)' Enter the channel type (ITU, USA, P , WX) and 2-digit channel

number. 3) Press the ENTER] key.

The memory channel list can be printed. 1) When the [SHIFT] & [2] or [3] keys are pressed, the registered

memory channels are scanned. 2) The channel types and number vary with scanning. 3) When the keys are pressed once again, the function is canceled and

the radio is waiting state in CH16. 4) When the handset is picked up or the [CHI61 or the [CH70] or

[DISTRESS] key is pressed, the function is canceled. 5) When the function is in execution, the indicator is on.

PS (Pause scan) The channel is changed every 0.5 s. When a signal is received, the channel is held for 5 seconds and changed to the next one. BS (Busy scan) The received, the channel is held until the signal is lost.

5.3.6 Test Flow

then select "3"

P r e s s E d kc

Press key, Press E d ke , F ' r e s s B k e y Press ke!

Send B-signal /Sepll Send Y-signal I /

Vthen select "0" then select "1 " then select "2"

Stop ? r Test function ? Test Function ? 0 : Loop(M0D-DEM) test ' 1 : Send B-signal '

u P r e s s E d key u P r e s s m key

Test function ? 2 : Send Y-signal

vthen select "0" ,

Press key Press= key

T - p then select "2" then select "3"

Loop tes; 3 : Send I Format specifier ? Loop test ?

Non-error STOP ? Loop tes Non-em I Nature of distress ?

Times : 1 Interval : 45 sec.

Loop test (Message) ERRIMSG 01 1

ERRIMSG 01 1 Retry End MENU

I I

I Time 14:40 UTC I 1 OK Edit Non I

1 Communication type ? ( Telephone-simplex

IT&, key u Press- key 1

] Times : 1 I 1 Interval : 45 sec. I

1 ERRIMSG 01-1 1

pGeE-1 R e t ~ End MENU

Press E d key. then select "3" 7 hen select "5"

Test function ? Test function ?

- ~ r e s s m key

71

Press b a key. - then select "3" then select "4"

Loop test ? r Loop test?

Loop test (Y-sig.) Loop test (DOT-sig.) Non error STOP ?

1 1

I d F d key

y1 Stop test : STOP key

PresdSTOd key

then select "6" Test function ? 6 : WKR test

F'resslENTER] ke

Sto test : STOP ke U I I Press key ,. "smkey h then select "4" y( I

I Test function ? I I

PROM : OK RAM : OK

5.3.7 Initialize Flow 112 VHF TIR controlled

~ r e s s m k e y (when the ID No. isn't entered into the radio)

s s w l k e y (when the ID No. is already entered into the radio), then select "5"

x MENU ?

z 22 00 : Register address 07 : Answer autohanu. m a - 01 : Address list 08 : Navigational IIF

Select "10"

Select "01" L

02 : File list 09 : Weather CH set 03 : Date B. time 10 : USA CH set W : Set up list 11 : Self-ID check 05 : Printer function 12 : Return lo MENU 06 : Telecornrnand

Set up 00 : Register address

Address 00120 used 01 : Not used

P r e s s E d key

lnput address 01: 1 h

Q)

Select "@9" S e k t "08"

Select "07"

\ 1 R e s s m key

I lnput other address? I

8 2:

V) 1 Yes End List I V)

I I X

2 Q

I Select "06" Select "05"

, Select "04" Select "03"

Set up ?I 01 : Address list ,-I 02 : File list

Print out Print out

- Set up 03 : Date & time

APR15'95 l7:24 UTC OK Edit I

15 Input new date, then pess E E & e y J.

I Hour : Minite UTG (

Input new time, ther press key

Print out

15'95 1 7:24 UTC ( (

, - Month - Day APR -

Input new date, then presslENTERey J.

Input new time, then press -key

Print out

Set up

k e s s m key

On-line-print ? 0 : All message 1 : Receive MSG only 2 : Transmit MSG only 3 : Don't print

--I--

1 06 : Telecommand I

Press- key I--

1 : Telephone-duplex Select Refuse 1

Select one of "0" to "3", then press -4 key

~ P r e S S ~ ~ key

1 2 : Data I

3 : Facsimile I Select Refuse I ( Communication type 1

I

Press(RuTFll( key

5.3 -7 Initialize Flow 212

Set up

Send answer ? w - Select either manual or auto, then press-4 key

Select device ? 0 : No device 1 : NMEA0183 GLL 2 : NMEAOl83 GGA 3 : NMEA0183 RMA 4 : NMEA0183 RMC 5 : NMEAOl82 6 : JLE3### 7 : LR717 8 : NRD722D

08 : Navigation IIF . U YI o m , - o 2 m a -

Select except "0" . 4 then press,ma key

l ~ a u d rate (bps) ? I 1110 ;200 2400 48001

Select one of them. J( then press -key

Select either 7bits of 8bits, then press- key , J.

Parity ?

Select one of them.

Stop bit ?

then press m d key

Polarity ?

Select either normal or invert, then press-d key

Set up 09 : Weather CH set

Weather 4CH used 01 : F No. 1

Input "02"

( Weather 4CH used I

I

I Weather 4CH used 03 : F No. 19 I

1 4 Input 'YM"

04 : F No. 22

I Weather 4CH used I 1 05 : Not used I

4 2 e s s ~ key

I Weather CH set 1 w I n ~ u t file No.. then

Weather channel

Press Trd ENTE key

?rc+iiGZ key

I used 1 i i used

Input "03"

lnput "04"

lnput "05"

H used I

lnput file No., thcn A 'press-] key I 2 : End 7

Set up L i L J USA avairable CH

i Select either select or refuse, then press

i -key i at all duplex channel

USA avairable CH

Printout

Set up 11 : Self ID check 1

T

I Self identification I

?? SELF ID ??

Set up 13 : Set self-ID 1

I pf identification ? I

OK Edit I

I Group ID ? I

Group ID : Delete

6. Maintenance and Adjustment

6.1 Cleaning and Checking Connectors, etc.

This work shall be conducted after the power is off.

No. Item Description

1. Cleaning (1) Wipe the panel surface, knobs and covers gently with soft cloth and silicon oil.

(2) Remove dust out of the inside with a brush or the cleber.

2. Loosen screws (1) Check screws, nuts and knobs for looseness and tighten correctly if needed.

(2) Check ICs inserted into sockets for looseness, and insert correctly if needed.

3. Loosen connectors (1) Check connectors for looseness and tighten correctly if needed.

6.2 Self Diagnosis

The self diagnosis function facilitates the check of operation. Selecting " 5 : Test " on the MENU selection screen displays the test function selection screen as follows:

Test function ? 0 : Loop (MOD-DEM) test

1 : Send B-signal ( 2100Hz sending) (2) 2 : Send Y-signal ( 1300Hz sending) (3) 3 : Send dot (B-Y) (Dot sending) (4) 4 : Check memory (ROM and RAM check) (5) 5 : Check LED & buzzer (LED and alarm check) (6) 6 : WKR test (DSC receiver test) (7)

* Test items 1 to 3 are not exercised unless the transmitter is connected.

(1) Modulator-demodulator Loop Test Loop test signal selection screen

Loop test ? 0 : Send message

1 : Send file 2 : Send B-signal 3 : Send Y-signal 4 : Send dot (B-Y)

The loop test is to input the signal generated by the modulator to the demodulator for checking the operation of the modulator and the demodulator.

(a) Send Message Refer to 5.3.2.1 Message sending of Section 5 OPERATION for upto the selection of answer request.

Here, selection of answer request display the test time and test intervals selection screen.

Times : 75 Interval : 60 sec.

Setting range of times : 1 to 65536 Setting range of intervals : 40 to 32767

After setting the times and intervals, the following screen is displayed by hitting the ENTER Key.

Loop test (Message) ERlUMSG : d n n

ERRIMSG : d n n implies :

mm ; the number of messages without agreement between transmission and reception.

nn ; the number of messages transmitted.

On completing the test as many times as preset, the following resultant screen is displayed.

ERWMSG 0175 End MENU

Relay : Test is retried from 0 times. End : The loop test signal selection screen is displayed. MENU : The MENU selection screen is displayed.

(b) Send file

Selecting "send file" , displays the following file selection screen.

Send FILE message ? 01 : *

Mark * is filled with the file name.

The operation after file selection is equal to (a) above. Display during test is as shown below :

Loop test (FILE)

(c) Send B-signal

Selecting "Send B-signal" displays the following screen.

Loop test (B-sig.) STOP ?

The received data bit stream is checked for a second.

- - I Loop test (B-sig.) I Non-error STOP ? I

When there is no error, "Non-error" is displayed.

When there is error, "Error" is displayed. To terminate the test, hit the STOP key.

(d) Send Y - signal

Equal to the case of B signal. Read (B-sig.) as (Y-sig.).

(e) Senddot (B-Y)

Equal to the case of B signal. Read (B-sig.) as (Dot-sig.).

(2) B signal (2100Hz) sending to external

The display during sending is as shown below. To terminate, hit the STOP key.

Sending B-signal 1 STOP ?

(3) Y signal (1300Hz) sending to external

Equal to the case of B signal. Read "B-signal" as '9'-signal".

(4) Dot signal sending to external

Equal to the case of B signal. Read "B-signal" as "Dot-signal".

(5) Check of ROM and RAM

The following is displayed to check ROM.

Checking PROM Rest : * * kbytes

Mark * * shows the residual capacity of the ROM check. Succeeding the ROM check, the RAM check is done and the result is displayed.

"OK" is indicated for the acceptable result, and "NG" for the unacceptable results.

(6) Check of LED and alert tone

When the LED reporting the called state (distress urgency : red, other : green) lights and the tone sounds pee, it is the normal state. The display is as shown below :

LED & buzzer test Stop test : STOP key

(7) DSC receiver test

It is normal when the frequency indication stops at 21 87.5 kHz, the DOT DETECT LED lights and the tone sounds pee.

* Be sure to set the MONITOR switch to ON for this test.

The display is as follows :

I WRK Test Stop test : STOP key

6.3 Fault Detection and Troubleshooting

Before troubleshooting, check the power supply and the connectors. Be sure to turn OFF the main power switch while troubleshooting.

Symptom

1. Power cannot be turned ON.

3. No sound was emitted when the DSC receiver was tested.

Cn

Probable causes

I

a ~ l o w n fuse

cn 2. An error occurred when a loop test was conducted.

O T h e power unit is faulty.

O T h e identification number for the individual call is not the number of your station.

3 T h e CONT unit is faulty.

DThe handset is off the handset holder.

3Ei ther the speaker or the amplifier is faulty.

B ~ i t h e r the receiver or the CONT unit is faulty.

Remedies

Check the A U D C fuse in the power unit, and replace it if it is blown. AC:SA DC:15A

Check the Z/O voltage of the power unit U1, and replace the unit if the voltage is abnormal. ACinput 90- 115 V DC input 24 V + 10% Output from the power supply DC 13.8 V + 10%

OChange to the number of your station. Replacement of the CONT unit

@ ~ e ~ l a c e the CONT unit.

Set the handset in the handset holder.

If no sound is emitted during key operation, replace the RX

Replace either the RX or CONT unit.

Replacement and adjustment

Replacement of the power unit U1 (Figure 6-1) a ~ e m o v e the power unit by loosening the four setscrews.

@Remove the AC/DC input terminal, 13.8 V output connector, and SWconnector on the power unit.

Replacement of the CONT unit (Figure 6-2) m o p e n the panel of the main unit by loosening the two setscrews.

he CONT and KEY units are fixed to the panel by machine screws. To replace the CONT unit, remove the three connectors attached to the RX, H.S and panel units and the six fastening screws, and a screw fastening the N2(78M05)3 terminal regulator.

Replacement of the RX unit (Figure 6-3) D o p e n the panel of the main unit by loosening the two setscrews.

3Remove the two coaxial connectors, the external connection terminal, and the six fastening screws on the RX unit.

Symptom

4. Transmission cannot be performed.

5. A buzzer sounds when the press switch of the handset is pressed (for transmission).

ul 4

Probable causes - -

he handset is in the handset holder.

@The press switch of the handset is faulty.

@The PA unit is faulty. (Transmission output is reduced.)

Remedies

Remove the handset from the handset holder.

- --

Connect a tester to pins 1 and 2 of the conncctor of the handset and turn ON the press switch. If there is no continuity between pins 1 and 2, replace the handset

Replace the RX or CONT unit.

@Replace the PA unit.

Replacement and adjustment

Replace the RX or CONT unit in the same manner as in the cases of symptoms 2 and 3.

~ - - ~-

Replacement of the PA unit (Figure 6-4) Qopen the panel of the main unit by loosening the two setscrews.

@Remove the RX unit in the same manner as in the case of symptom 3.

@Remove the coaxial connector and the 13.8 V input connector attached to the PA unit,and then remove the six screws fastening the PA unit and the two screws fastening the A1 (M57710A POWER AMP IC).

Adjustment of the PA unit a ~ o n n e c t the terminal-type power meter to the ANT terminal, set

the CH to CHI5 and the transmission output switch to 25 W, and then press the press switch of the handset.

O ~ d j u s t the R37 so that the terminal-type power meter may indicate 22 Wk2 W, and make sure that the frequency counter indicates 156.750 MHzkl.5 MHz.

@Set the transmission output switch to 1 W, and make sure that no alarm sounds when the press switch of the handset is pressed.

Symptom

6. No modulation

7. The LED on the display unit cannot be turned ON.

Probable causes --

@A break in the handset cord

he RX unit is faulty.

OTX UNLOCK

a ~ i g h t i n g control operates.

@The KEY unit is faulty.

-

Remedies

Check the handset cord, and replace it if a break is found in if

Replace the RX unit.

a ~ e s e t lighting control by the lighting (Shift + [O]) key.

O ~ e p l a c e the KEY unit.

Replacement and adjustment

Replace the RX unit in the same manner as in the case of symptom 3.

Replacement of the KEY unit (Figure 6-5) @open the panel of the main unit by loosening the two setscrews.

O ~ e r n o v e the CONT unit in the same manner as in the case of symptom 3.

he KEY unit appears under the CONT unit. Remove the bracket after removing the two screws fastening the bracket. Then, remove the six screws fastening the KEY unit and the two connectors attached to the LCD.

Figure 6-1 Replacement of the power unit

Figure 6-2 Replacement of the CONT unit

60

Figure 6-3 Replacement of the RX unit

shield cover

ctor

Figure 6-4 Replacement of the PA unit

fastening screw

Figure 6-5 Replacement of the KEY unit

6.4 Adjustment

This equipment practically requires no adjustment in normal use. If any part or instrument of this equipment is checked or repaired when a fault occurs, confirm that every part is in normal condition by referring to the circuit diagrams, circuit descriptions ,test results and so on. To adjust this equipment, setting of the transmit-receive frequency, switching between transmission and reception, and other operations are needed by using the key switches on the front panel.

6.4.1 Setting of the transmission output After connecting the high-frequency power meter to the antenna connection plug, set the CH to CHI6 to bring the equipment to the transmitting state, adjust R37 of the PA unit,and set the output to 20-25 W. Then, select 1 W for transmission output, adjust R26 of the PA unit, and set the output to 050.9 W.

6.4.2 Adjustment of the VCO (1) Receiving VCO Connect the digital voltmeter to the X15, and adjust L2 of the RX unit to set the lowest frequency (CH06) down to 1 V and the highest frequency (CH88) up to 5 V. (2) Transmitting VCO Connect the digital voltmeter to the X15, and adjust L7 of the RX unit to set the lowest frequency (CH60) down to 1 V and the highest frequency (CH88) up to 5 V.

6.4.3 Adjustment of the transmit frequency Set the transmission output to the 1 W mode. Connect the frequency counter to the antenna connection plug via the attenuator and measure the frequency. Use the trimmer of B5 (TCXO) of the RX unit to set the frequency.

6.4.4 Adjustment of the maximum frequency deviation Set the transmission output to the 1 W mode. Connect the FM linear detector to the antenna connection plug via the attenuator, and bring the equipment to.the transmitting state by setting the CH to CHI6 (156.8 MHz). Add an audio signal (1 kHz, +5dBml600 Q) through the external connection terminal X3 (7.9), and adjust R78 of the RX unit to set the frequency deviation to approximately 4.7 kHz.

7.2 Connection Diagram of RU224A

ANTENNA

- M-R

'' M-P

, N-P

Y

I APC I NJM2904

z 0 \

2 \

\ \ \ HCOO

Hc74 I.OGlC HC86 HC161

SQUELCH

BLOCK DIAGRAM MARINE VHF RADIO RU224A

i ANT

TERMINAL' ' CONNECTOR EXTERNAL CONNECTION PRINTER

A2 CONT

- A4 POWER SUPPLY

CIRCUIT DIAGRAM MARINE VHF RADIO RU224A