Midland Syn-Tech 70-342XL, 442XL, Syn-Tech 70-442XL Service Manual

VHF

(WIDE

BAND)

SERVICE

MANUAL

LAND MOBILE RADIO

1690

North

Kansas

Topping Avenue

City,

Missouri

bUVUUU

64120

MANUAL

09-342/442 XL SM-8/86-1.5M

NO.

70-342442

PREFACE

70-342https://manualmachine.com/442~~

This service manual the 70-342XL and 70-442XL transceivers. In the first section of this manual, after transceiver description and specifications, instructions

for transceiver preparation

stallation, and summaries of available support equipment. The second section of this service manual, entitled SERVICING,

dedicated to transceiver repair. Troubleshooting flow charts for locating likely problem General information follows, such replacement instructions and realignment procedures.

Transceiver circuitry herein respectively. Each PC board diagrams; Each schematic page has be vi.ewed with

Because the PC boards have components and plating on both sides, layout diagrams show superimposed images of plating patterns and respective other-side-component maps. Any double-image layout of the three PC boards can be viewed with their respective schematic without turning pages.

all

of which can be viewed with their respective schematics.

it.

is

intended to facilitate set-up and service of

are

found-- programming, calibration, ir-

areas

is

contained on three PC boards and categorized

a

list

are

in the beginning of t-his section.

as

chip component identification and

is

detailed in text, charts, and

of other applicable diagrams that can

is

,

Information in this book of the variety of readers' requirements, details of option add-ons

are

OPTIONS, each add-on kit.

As

buted on the following forms:

Many useful facts and tips intends to service several of the transceivers described herein,

spending

not included.

is

provided for allocating technical literature acquired with

necessary, service manual supplements

Manual Addition (MA)

Change Notice (CN)

Manual Correction (MC)

Technical Bulletin (TB)..For solutions to field problems and tips

time

to read applicable text

is

A

divider

.....

......

focused on the basic transceiver. Because

at

the end of this book, entitled

will

For supplemental information useful in

product alignment, service, or improvement. Printed on BLUE paper. For circuitry change details made during production by model and Printed on YELLOW paper.

...

For correcting literature errors not related to production changes. Printed on GREEN paper.

for performance improvement. Print.ed on PINK paper.

are

provided in the text. If the reader

will

be published and distri-

save

time

serial

in the end.

number.

TABLE

OF

Preface Table of Contents Description 3 Specifications:

ElPROM Programming:

Transceiver Calibration:

Installation:

Automotive Receiver Interference 31 Optional Accessories Service Equipment 37 Service Tools Optional Feature Add-on Kits 39

CONTENTS

.................................................

.......................................

70-342https://manualmachine.com/442~~

PAGE

ii

1

.............................................

General Transmit Receive Scan and CTCSS

Programmable Parameters

H1

Version Programmer Software 10 ElPROM Module Removal Programming

Set-up Error Codes Procedure 20

Instructions 22 Under-Dash Configuration 24 Trunk-Mount Configuration Under-Dash Power/Accessory Plug 26 Trunk-Mount Power and Accessory Plugs 28

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4

5

6

7

9

10

11

18 19

25

35

38

............................

SERVICING

Troubleshooting Charts:

General 45 CPU/Phase-Lock-Loop Transmitter Modulator Receiver

Component Replacement:

Chip Component Identification Replacing Components with Leads Chip Capacitor and Resistor Replacement

Complete Alignment:

Set Up 53 Error Codes Realignment Factory Presets

.............................................

.................................

.........................................

...........................................

............................................

.......................

.....................

.............

..............................................

.........................................

.....................................

continued

46

47

48

49

50

51

55 55

60

......

SERVICING continued:

Circuit Analysisf

Transmitter Board Microprocessor Pinouts Chart RF Power Amplifier Board

Receiver Board Simplified Squelch Circuit Schematic Metering Block Diagram 77 Under-Dash Circuitry:

Under-Dash Interconnect Diagram

Front Panel Schematic Diagram

Front Panel PCB Layouts

70-342XL/442X~ Receiver PCB Layouts

DC Voltages

70-342XL Receiver Board Schematic Diagram

Trunk-Mount Circuitry:

Trunk-Mount Interconnect Diagram

Control Head

Control-Cable Interface Board

DC Voltages - Receiver Board

70-442XL Receiver Board Schematic Diagram

Transmitter Board:

DC Voltages - Transmitter Board

Microprocessor Pinouts (Duplicate Chart) 89

RF Power Amplifier PCB Layout 90

E/PROM Module Layout 90

Transmitter PCB Layouts

Transmitter Under-Dash Exploded Mechanical

70-2301 Microphone

70-2195 Hang Up Box Trunk-Mount Exploded Mechanical Parts List 97 Parts Ordering 109

................................................

...........................................

..............................................

..........................................

...................................

........................

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......................................

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-

Receiver Board

........................

...........

....................

........................................

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........................

...........

.....................

............

.......................

................................

.............................

Board Schematic Diagram

View

Detail

...............................

..............................

View

.................

.....................

....................

61 63 69 71 75 76

78 80

81

82

83

84

85

86 87 87

88

91 93 94 95 95

96

OPTIONS

...................

GENERAL DESCRIPTION

The MIDLAND SYN-TECH 70-342XL and 70-442XL VHF wide-band Land-Mobile transceivers are mobile two-way radios designed to operate on FM channels between 136 to 174 MHz. There are two varieties of the SYNTECH 70-342XL and 70-442XL transceivers, each designed to operate on different channel frequency range: the A-band radios (70-342AXL 442AXL) on the 136-163 MHz range; the B-band radios (70-342BXL 442BXL) on the 148-174 MHz range. SYN-TECH transceivers have the capacity to operate on up to eighty operator selectable channels, each of which can be programmed in the service shop.

is

The SYN-TECH 70-342XL transceiver

It

ing. panel for easy access to the operator. The SYN-TECH 70-442XL transceiver location.

receptacle

long Control Cable that interconnects the 70-442XL remote unit with

its

Control Head. The Control Head contains all the operator controls and operator.

As

the SYN-TECH 70-342 and 70-442 transceivers, the XL models are wide-band radios. Electronic tuning of critical stages allow them to operate over a 24 MHz spread of channel frequencies.

has a control knobs, push buttons, and display all on a front

is

configured for mounting in a vehicle trunk or other remote

It

does not have front panel controls; instead

in

its

face-piece. The receptacle accepts the 4-meter

is

much smaller in size for mounting where accessible by the

configured for under-dash mount-

70-342https://manualmachine.com/442~~

&

it

has a 34-

is

used to

a

70713-

It

5

A

is is

The XL models are revised 70-342 and 70-442 transceivers that used KHz for their main VCO comparator frequency. The 70-342XL and 70442XL models use 2.5 KHz, thus allowing channel frequency increments of 2.5 KHz for half-channels.

as

Many optional features, such Complete add-on kits for field installation are readily available.

listing

Operating parameters such and a variety of feature timing and codes in an alterable memory module for easy customizing. The plug-in memory module E/PROM Programmer.

The 70-342XL and 70-442XL transceivers contain three major printed circuit boards. The Transmitter Board contains transmitter, synthesizer, and microprocessor control circuitry. components facing up, on the top side of the chassis center divider. The Receiver Board also lays horizontally, but on the underside of the chassis divider with components facing down. The third PC board the RF Power Amplifier Board located inside the rear heat sink. accessible by removal of the heat sink top cover.

with

brief kit descriptions can be found in later sections.

as

channel frequencies, CTCSS frequencies,

is

reprogrammable in the service shop using the MIDLAND

CTCSS, can be added at the factory.

are

electronically contained

It

lays horizontally, with

SPECIFICATIONS

OPERATING VOLTAGE: Nominal....

Range 10.5 to 16 VDC

..........

GENERAL

....

13.6 VDC, negative ground

70-342https://manualmachine.com/442~~

TEMPERATURE RANGE ANTENNA IMPEDANCE MICROPHONE FREQUENCY CONTROL

FREQUENCIES OF OPERATION:

Models 70-342AXL1442AXL 136 to 162 MHz

Models 70-342BXLl442BXL 148 to 174 MHz

CHANNEL CAPABILITY: Standard CHANNEL FREQUENCY SPREAD without retuning:

FREQUENCY TOLERANCE

DUTY CYCLE

.........................

..................-

..................

.......

......

Transmit....

Receive.

AND

STABILITY..+/- 5 ppm both TX and

.....

.........

30°C to +60°C 50 ohms, unbalanced Dynamic element (with amplifier) Phase-Lock-Loop synthesized with

EPROM Programming

Up to 80 transmit and 80 receive

24 MHz 24 MHz

2.5 ppm optional

+/-

2.0 ppm'optional

+/-

Intermittent. 1 min TX, 4 min

(Per EIA RS-152B)

maximum maximum

RX

(standard)

RX

HIGH

VIBRATION STABILITY SHOCK STABILITY... CURRENT

DIMENSIONS (H

WEIGHT:

HUMIDITY. 95%

DRAIN:

Standby Receive..

Transmit (40W

Transceiver (70-342XLl442XL) 65xl88x270mm (2.6" x 7.4" x 10.6") Control Head for 70-442XL 5Ox88x80mm (2" x 3.5" x 3.2") Speaker for 70-442XL 100x100x77mm (4" x 4" x 3")

Transceiver (70342XL1442XL) Control Speaker

--All

.....................

................

.................

....................

..................

@

x

W

x D):

50ohms)

....

at

50°C per EIA RS-152B, sec.13 Per EIA RS-152B, Per EIA RS-152B,

0.35 ampere DC (max)

1.00 ampere DC (max)

8.50 amperes DC (max)

sec. sec.

14 15

....

.......

............

.....

Head for 70-442XL 0.8 Kg (1.8 lb)

for 70-442XL

specifications subject to change without notice.--

............

.......

3.15

0.71 Kg (1.58 lb)

Kg (6.96 lb)

SPECIFICATIONS

TRANSMITTER

Refer to EIA RS-152B and DOC RSS-119-Issue 3 for Method of Measurement and Standard of Performance.

70-342https://manualmachine.com/442~~

CARRIER POWER OUTPUT

MODULATION SYSTEM

AUDIO FREQUENCY RESPONSE Per EIA and DOC specifications

AUDIO HARMONIC DISTORTION 3% THD

SYSTEM DEVIATION

MODULATION LIMITING

HUM AND NOISE

OCCUPIED BANDWIDTH...........

TRANSMIT CARRIER ATTACK TIME

CONDUCTED SPURIOUS EMISSIONS.

......................

...............

..................

...........

..........

...................+/-

................

......

.......

......

40

watts minimum,

adjustable from 20 to 40 watts

Phase Modulation

(1 KHz tone at 3.0 KHz deviation)

5

KHz maximum

Instantaneous peak clipping with low-pass audio filtering

50 dB

Less than -60 dB of carrier power

30 KHz outside carrier frequency

100 ms max. for

Less than

25

50%

rated power

uW from 1 to

1000

MHz

MICROPHONE INPUT LEVEL.

OUTPUT PROTECTION: Shall withstand withcut damage,

OUTPUT STABILITY: Shall not exceed spurious emission limits herein

--All specifications subject to change without notice--

............-

operation into a 20:l load mis-match with any standing wave variance.

while operating into a 5:l load mis-match with full standing-wave variance.

8

dBm

+/-3

dB at

600

ohms

5

minutes of

SPECIFICATIONS

RECEIVER

Refer to EIA RS-204C and DOC RSS-119 for Method of Measurement and Standard of Performance.

....

SENSITIVITY: 12 dB SINAD......

0.25 uV into 50 ohms

70-342https://manualmachine.com/442~~

SQUELCH SENSITIVITY: Tight

Threshold....0.2 uV maximum or

SQUELCH BLOCKING.. 13 dB

RECEIVER ATTACK TIME......... 100

(squelch release) RECEIVER SQUELCH CLOSING TIME...

ACCEPTABLE RF DISPLACEMENT.........+/- 3.5 KHz minimum

ADJACENT CHANNEL REJECTION

SPURIOUS RESPONSE IMMUNITY.... 85 dB

INTERMODULATION IMMUNITY..... 75 dB

AUDIO POWER OUTPUT:

Under-Dash Radio (70-342XL)

Trunk-Mount Radio (70-442XL) 5 watts at 5% THD into the 3.2 ohm

.................

........

......

.........

.....

......

.....

1.0 uV minimum, 2.0 uV maximum

6

dB SINAD

ms

...

200

ms

80

dB at +/-30 KHz

1

watt at 5% THD into its internal

speaker, or

5 watts 5% THD into a 3.2 ohm

external speaker

....

external speaker

AUDIO FREQUENCY RESPONSE.....

HUM AND NOISE: Un-squelched

Squelched 50 dB

CONDUCTED SPURIOUS EMISSIONS.. 200 uV across 50 ohms

INTERMEDIATE FREQUENCIES 21.4 MHz (1st) and 455 KHz (2nd)

--All specifications subject to change without notice--

......

.......

..........

.....

...........

6

Per EIA and DOC specifications

40

dB

(800

from DC to 1 GHz

pW)

SCAN OPTION

Several of these parameters

are

programmable by E/PROM programming.

CHANNEL CAPACITY

OPERATOR CONTROL OF SCAN

PRIORITY CHANNEL SELECTION Any channel selectable by the oper-

INDICATION OF PRIORITY DETECTION

KEY-UP CHANNEL REVERT

EXTRANEOUSLY BUSY CHANNEL SKIP

PRIORITY CHANNEL SAMPLING RATE

SIGNAL DETECTION

...................

...........

.........

...

..............

.....

...................

2 scan groups of 64 each

(duplicates allowed)

Three modes selectable by push buttons

ator using the channel push buttons

Two-beep audible alert (elective) Transceiver transmits on Priority

channel or

(depending on scan mode selected)

Channels can be skipped in scan by

DOWN

Every 4 or 8 channels, or every

or 2 seconds during scan hold

of carrier presence or vacancy; or of correct CTCSS tone presence or

vacancy with

channel selection

last stopped channel

1

carrier

SCAN RESUME DELAY

SCAN SPEED (with standard timing):

Noise squelch busy detection 20 idle channels per second CTCSS detection

CODE FREQUENCIES

MODULATION LIMITS 500 to 1000

DECODE SENSITIVITY

RECEIVER RESPONSE TIME

ENCODER RESPONSE TIME 50 TRANSMITTER TONE DISTORTION

AUDIO

DISTORTION WITH CTCSS TONE

..................

.....

..................

CTCSS OPTION

...................

..................

.................

.............

..............

........

...

0.3, 2.5, or 5 seconds or lock

3

All

Less than 5 dB SINAD

200

5%

10%

&

hold until

channels per second if all busy

EIA standard from

Hz

ms

maximum

ms

maximum

reset

67

carrier

to 241.8Hz

deviation

--All

specifications subject. to change without notice--

7

E/PROM PROGRAMMING

The 70-342XL and 70-442XL transceivers contain an Erasable/Program-

mable Read Only Memory (E/PROM) module. The module holds specific

customer frequencies, feature selections, and other parameters that determine radio operation.

Before final alignment and check, the module must be reprogrammed with customer specifics. If any option add-on kits are to be installed, appropriate parameters may also need to be programmed as instructed in respective kit installation literature.

To change ElPROM electronic information, the plug-in module must first be erased by exposing it to ultraviolet light using the MIDLAND 701100/1101 ElPROM Eraser. Then, reprogramming is necessary using the MIDLAND 70-1000 ElPROM Programmer. Operation parameter information is entered into the Programmer through its keypad, converted into binary data useful to the transceiver, then written into the E/PROM.

The following are programmable operation parameters in the SYN-TECH mobile transceivers. See the 70-1000 E/PROM Programmer Operator's Manual (No. 70-999113) for details.

1.

All eighty transmit and eighty receive channel frequencies

2.

All standard CTCSS tones for each TX and RX channel (requires installation of the CTCSS module within the transceiver)

3. Time-out-timer time (maximum continuous transmission duration)

4.

Scan parameters as follows:

a. Two scan groups, each containing up to sixty-four

channels

A

b.

c. Either presence or absence of carrier or correct CTCSS

d. Channel sampling rate (time spent looking for carrier

e. CTCSS decode time (time allotted for decoding after

f. Scan hold time (delay of scan resume after channel

g. Post-transmit scan hold time (delay of scan resume

h. Retention of scan list channels deleted (skipped) by

5.

Busy channel lockout with or without alert tone to the operator. Adding jumpers allows busy channel inhibit by

CTCSS tone status. See "BCLO JUMPERING".

6.

Transmit-to-receive changeover delay of up to 200ms for

special options.

7. Last selected channel recall on power-up may be disabled.

variety of priority/scan channel revert arrangements

utilizing the two channel lists.

tone to indicate a busy channel

presence on each channel)

carrier is detected)

clears)

after PTT release)

operator activation of the DOWN selector while in scan mode. Normally, these selections are erased by release of the SCAN and PRI push buttons and power-down. Programming limits erasure to power-down only.

70-342https://manualmachine.com/442~~

H1 VERSION UPGRADE

The E/PROM programmer, model 70-1000, must contain H1 or later version software to program all features and parameters into the 2-273 E/PROM modules that are used in the 70-342XL and 70-442XL transceivers. The version level of software installed in the programmer is identified for one second in the two far right digits displayed after power-up. If your programmer contains software that,is older (lower letter) than the H1 version, upgrade is required. To date of this printing, the newer L3 version software is current and available (in its own E/PROM) in Update Kit No. 70-1411. The 70-1000 Operator's Manual also has been rewritten. The May, 1985 printing can be ordered as MIDLAND part number 70-999113.

CDCSS OPTION

If the Continuous Digital Coded Squelch System option is installed in the transceiver, the ElPROM Module is different. This Module, MIDLAND number 70-2402, is larger in size to accommodate an additional receptacle for connection to the CDCSS board. When programming, the ElPROM type selection entered into the Programmer is the same as for the standard EIPROM.

ElPROM MODULE REMOVAL

The E/PROM module is a small (1"

x

2") plug-in printed circuit board that contains IC951 and IC952, and is labeled 2-273. It is located on the Transmitter Board, over the microprocessor IC901. For replacement purposes, the ElPROM module model number is 70-2401.

Always disconnect primary power to the transceiver before removing the E/PROM module. Loosen the four transceiver top cover screws and lift the cover off. Pull the E/PROM module straight upward to separate it from its two connectors (see below).

70-342XL

OR

70-442XL

TRANSCEIVER

E/PROM MODULE LOCATION

E/PROM PROGRAMMING

PROGRAMMING The following E/PROM programming procedure covers most programming for

transceiver operation. Certain infrequently modified parameters are

as

excluded (parameters listed

programming procedures can be found in the Programmer Operator's

Manual.

Heed this precaution:

Do not apply or remove AC-line power to the Programmer while an E/PROM module able, to plug the module onto the Programmer until all parameter information ready for the BLANK-WRITE-VERIFY operation (step 25).

is

plugged into

is

keystroke entered. Connect the module only when

4h, 6, and 7 on page nine). Complete

it.

It

is

not necessary, nor advis-

70-342https://manualmachine.com/442~~

1.

2. Turn the 70-1000 Programmer on. One of these self-test messages

3.

Erase the E/PROM module in the 70-1100/1101 Eraser. Assure the E/PROM window Refer to the Eraser instruction manuax for details.

must appear in the FREQUENCY display for one second: "PASSOL3",

"PASSlL3", "PASSOHll', or "PASSIHll'. The the required software revision level programmer. After two seconds, "TYP" should appear in the BAND display. If an earlier version software VERSION UPGRADE preceding.

Enter the heading (not necessary for transceiver operation, but recommended for organization) by pressing [MANUAL], then [ENTER],

then the following:

a. The second part of the transceiver model number ('342A1,

for example). Then [ENTER].

b. Transceiver eight digit

Then [ENTER].

c.

First three digits of a ten digit customer number

(ex.: '123'). Then [ENTER].

d. The last seven digits of the customer number

(ex.: '9ABCDEF1). Then [ENTER].

e.

The month numerically (ex.: March = '3'). Then [/I. f. The date ('1' through '31'). Then [/I. g. The

h. Press [RESET] to close heading sequence.

is

last

clean, and

two digits of the year (ex.: '86'). Then [ENTER].

set

serial

exposure

H1

number (ex.: '12345678').

time

last

or L3

is

for 45 minutes.

two digits indicate

is

installed,

installed in the

see

H1

--E/PROM Type Selection--

4.

Press [l] to should appear. (If the transceiver contains either Talk-Around option 70-2815 or 70-2816,

by pressing [7] instead of [I]) Press [ENTER].

select

the standard 2-273 E/PROM Module. "2-273"

select

the Z-273TA E/PROM Module type

E/PROM PROGRAMMING

70-342https://manualmachine.com/442~~

5.

--Channel Frequency Programming--

The CHANNEL display indicates the numeric channel designator that appear in the transceiver display. The STEP display indicates what

entry

If an invalid frequency quency display frequency.

6.

Select the VHF band and 2.5 KHz PLL reference code by pressing

[2], then [Dl. "15d" should appear in the BAND display (if the transceiver has been modified with 70-2178 or 70-2179 High-Side Injection

[ENTER]. The Programmer should now be ready for channel

frequency entry.

is

to be made for that channel--

"1"

"2"

"3"

"4"

CHANNEL

desired receive frequency for channel

point. Then press [ENTER].

Kits,

=

receive frequency

=

receive CTCSS tone frequency or receive CDCSS code

=

transmit frequency

=

transmit CTCSS tone frequency or transmit CDCSS code

will

"1"

use band code [El instead of [Dl). Press

is

entered in the following steps, the fre-

flash. Press [CLEAR], then reenter the correct

and STEP

"1"

should now be displayed. Key in the

1

including the decimal

will

7. CHANNEL option or CDCSS code can be entered as described below.

CTCSS Key in the desired CTCSS tone frequency to be decoded including the decimal point (only standard EIA frequencies

are

Press [ENTER]. If coded squelch option

CDCSS Key in the desired three-digit standard decode code

(only EIA standard codes

in the FREQUENCY display. If signal after digits. carrier squelch operation

option

The Programmer contains

frequencies and CDCSS codes, any of which each this mode. Press again to increment through them one

are

stacked on top of the CTCSS tone

scrolling past the highest CTCSS tone. Press [C] to decrement through the displayed, press [ENTER] to program.

"l",

is

valid). The digits

STEP "2", should be displayed. If a coded squelch

installed in the transceiver, the CTCSS tone frequency

will

carrier

is

not installed, enter zero.

A

"-"

will

is

installed, enter zero.

a

table of EIA standard CTCSS tone

[Dl

to

call

lists.

When the desired frequency or code

appear in the FREQUENCY display.

squelch operation

are

valid). The digits

is

inverted, key [A]

appear. Press [ENTER]. If

is

desired or no coded squelch

the CTCSS tone frequencies and

at

a

time.

list,

and should appear when

is

desired or no

will

are

accessible in

The CDCSS codes

is

appear

E/PROM PROGRAMMING

70-342https://manualmachine.com/442~~

8.

9. CHANNEL

10. Repeat steps 6 through

--Center Frequency Programming--

To afford wideband capability, the self-tuned 70-342XL and 70-442XL

transceivers switch the operating range of their VCO's when selected channel frequency crosses controlled by the microprocessor and must programmed into the E!PROM. Center Frequency values entered into the E/PROM depend on the transceiver frequency band (A-band or B-band).

CHANNEL transmit frequency for channel Then press [ENTER]. If the transmitter channel

is

equipped with a coded squelch option, key in the desired CTCSS tone frequency or CDCSS code to be transmitted, or nothing for no tone/code transmission. Then press [ENTER]. The tone/code table can be used in this mode also.

channels. Channels may be skipped and left unprogrammed. Channels can be scrolled and re-accessed using the up and down arrows.

"l",

1,

"l",

STEP

enter zero.

STEP "4", should be displayed. If the transceiver

"3",

should be displayed. Key in the desired

1

including the decimal point.

is

to be disabled in

10

to program the remaining seventy-nine

a

range-center frequency. This switching

is

11.

12. STEP

13.

--Scan Channel Entry--

14. Channel and tone frequency entry

Scroll backward through the channel arrow push button. Whenever the channel accessed and "CF" appears in the CHANNEL display. Stop on the CF channel.

Frequency entry. Key in '148.12' if the transceiver

model (136-162 MHz range) or key in '160.92' if the transceiver

is

a

STEP Frequency entry (STEP 2 and 4 do not apply, therefore do not appear with the CF channel). Key in '147.20' if the transceiver

is

an A-band model (136-161 MHz range) or '160.00' if the

transceiver

[ENTER].

begin scan channel programming sequence. The display bgank except for the SCAN indicator.

0

to channel 79, the Center Frequency 'channel'

"1"

will

B-band model (148-174 MHz range). Press [ENTER].

"3"

will

also appear, showing readiness for receive Center

appear, showing readiness for transmit Center

is

a B-band model (148-174 MHz range). Press

list

is

complete. Press [SCAN] to

with the appropriate

is

looped backwards from

is

will

is

an A-band

be

There are two

list

the transceiver during scan operation differently, depending on selection of the PRI and SCAN push buttons and Function Mode

programming. Details of operation are found in both the transceiver and the Programmer operator's manuals.

can be up t.o 64 channels long. The two

lists

of scan channels available--A and B. Each

lists

are used by

E/PROM

PROGRAMMING

70-342https://manualmachine.com/442~~

15. Press [A] to program the display and the first the BAND display.

16. Key in the channel number to be scanned first in the press [ENTER]. While in the CHANNEL display.

17.

18.

19. When the

After [ENTER] display) and press enter. If you make an error, press [CLEAR] and enter. If the channel entered frequency entry steps above, the CHANNEL display indicate the error. Press [CLEAR] and enter

Continue entry of the A scan several scan sequence spots to cause

To

scroll through the

each sequence designator assignment. The highest designator

63.

in the STEP display and the lowest B designator (0) should appear in the BAND display. Enter B scan

list

highest

will

A

channels in the

list

is

pressed, the

increment to

list

entry

sequence designator

A

list.

list

it

sequence designator "0"

is

keyed, the channel number

1.

list.

A

list,

is

complete, press [B]. "b" should appear

same

manner as A list

"A"

will

A

list

Key in the second A scan channel

was

press the up and down arrows to

sequence designator (BAND

left blank in the channel

A

channel can be entered in

it

list

is

63.

appear in the STEP

will

a

valid channel.

to be sampled more often.

scan sequence

entry. Again, the

appear in

A

list,

will

flash to

appear

re-

then

see

is

2C. Press [RESET] to exit the scan programming mode. The Channel

frequency entry mode

"l",

The Busy Channel Lockout feature, Time-Out-Timer feature, and scan feature parameters these eight parameters need programming for most applications, therefore attention program the others (timing adjustments, etc.) can be found in the Programmer Operator's Manual.

21. BCLO Press [FUNC.] then [ENTER]. "FnC"

display and programming the Busy Channel Lockout (BCLO) feature,

active. Key in one of the following values, then press [ENTER].

If no entry value of for jumper considerations.

and the appropriate frequency.

are

is

given to only these four hereinafter. Procedures to

"1"

in the STEP display. Function Code

is

made, the transceiver

3

--no BCLO. Also

will

programmed in the Function Mode. Only four of

resume displaying CHANNEL

will

see

"BCLO JUMPERING'' in this section

operate per the default

appear in the BAND

"OM,

1,

for

is

now

STEP

E/PROM

21. continued... BCLO parameters:

Throughout Function Mode programming, the up and down arrows will sequentially select the Function Codes.

22. Time-Out-Timer "FnC" and "2" will be displayed. Key in the parameter value below, then press [ENTER]. When the transmitter is continuously keyed for the programmed duration, the timer disables the transmitter and applies an audible alert tone to the speaker.

The

default value of inoperative.

PROGRAMMING

O= BCLO without alert. No audible indicating tone will be

heard.

2= BCLO with alert. When the PTT button is pressed while ths

transceiver is inhibited, a tone will be applied to the speaker.

3= BCLO disabled. No transmit inhibiting per receive status.

to set the Time-Out-Timer duration as listed

timer is reset upon PTT release. If no entry is made, the

0

will be automatic, leaving the Time-Out-Timer

70-342https://manualmachine.com/442~~

O= Disable the Time-Out-Timer

1= 30 seconds

2=

60

seconds

90

3=

23. Press the up arrow four times to skip to Function Code 7. Function Codes 3 through

their default values. scan timing, refer to the Programmer Operator's Manual for procedure.

24. Priority Monitoring '!FnC1' and "7" should be displayed. Entering a value in this mode either disables priority channel

(see function is not programmed, the default is one Priority channel sampling every eight channels scanned, and one Priority sampling every second when scan is stopped on an active non-priority channel.

Key in a value listed below, then [ENTER], to program the desired sampling rates.

erato tor's

O=

1=

2= Sample the Priority channel once every four non-priority

3=

4=

seconds 7= 210 seconds

6

will automatically be programmed with

If

a special application requires altering

manual) sampling or changes its rate.

Sample the Priority channel once every four non-priority channels scanned, and sample it every second when scan is stopped. Sample the Priority channel once every eight non-priority channels scanned, and sample it every second when scan is stopped.

channels scanned, and sample it every two seconds when scan is stopped. Sample the Priority channel once every eight non-priority channels scanned, and sample it every two seconds when scan is stopped. Disable Priority monitoring

4=

120 seconds

5=

150 seconds

6=

180 seconds

If

this

25.

Scan Format "FnC1' and feature operates in three different mode formats--'Normal1,

'Modified', and 'Secondary'. Each

Manual.

"8"

should be displayed. The scan

is

described in the Operator's

While operating, scan Programming can CTCSS detection, absence of detected correct CTCSS tone with used in in special applications.

The parameter value determines both scan format and scan stop aspects

[ENTER]. The default value if no entry correct whether a coded squelch feature transceiver or not. If no CTCSS frequency nor CDCSS code programmed to a channel (steps 6-11), any odd value parameter programmed

(ex.: If

will

Function Code

* *

*

*.7=

$5

*

as

listed below. Key in the desired value and press

will

1

is

subtract 1 and operate per parameter 0.).

O=

'NORMAL' Scan Mode with scan stopped by carrier presence

1=

'NORMAL' Scan Mode with scan stopped by presence of

correct CTCSS tone or CDCSS code

2=

'NORMAL' Scan Mode with scan stopped by absence of

3=

'NORMAL' Scan Mode with scan stopped by presence of

without correct CTCSS tone or CDCSS code

4=

'MODIFIED' Scan Mode with scan stopped by

5=

'MODIFIED' Scan Mode with scan stopped by presence of

correct CTCSS tone or CDCSS code

6= 'MODIFIED' Scan Mode with scan stopped by absence of

carrier

'MODIFIED' Scan Mode with scan stopped by presence of

carrier

8=

'SECONDARY' Scan Mode with scan stopped by

9=

'SECONDARY' Scan Mode with scan stopped by presence of

correct CTCSS tone or CDCSS code

A=

'SECONDARY' Scan Mode with scan stopped by absence of

ca'rrier

b= 'SECONDARY' Scan Mode with scan stopped by presence of

carrier without correct CTCSS tone or CDCSS code

set

be decreased by one when read by the transceiver

programmed and CTCSS

8

--

is

stopped by detection of received signal.

scan-stop by noise squelch carrier detection,

carrier

carrier,

presence. The

is

disabled, the transceiver

or absence of

latter

made installed in the

is

1,

two

are

which

is

carrier

is

carrier

without correct CTCSS tone or CDCSS code

carrier

presence

,.

*

:

If the selected channel does not have a CTCSS tone or CDCSS code programmed to decrease this parameter value by one and operate accordingly.

26.

Parameter entry feature feature the Programmer Operator's Manual for programming procedures.

This concludes the Function Mode programming sequence. Press

[RESET] to exit.

is

complete. If the last selected channel recall

is

to be disabled, or the operator-deleted scan channel recall

is

to be disabled, or scan timing needs modification; refer to

it,

the transceiver microprocessor

will

E/PROM PROGRAMMING

70-342https://manualmachine.com/442~~

27. Plug the erased 2-273 ElPROM module onto the 70-1000 Programmer as shown in Figure

2.

2-273

MODE

EIPROM PROGRAMMER

PROGRAMING

EIPROM MODULE

THE

E/PROM MODULE

28. Press [FUNC.] key, then the [4/B.W.V.] key. The BLANK, WRITE, and VERIFY indicators module

is

programmed. "PASS"

tent in the E/PROM

will

is

correct. If the readout displays flashing

each illuminate in succession as the

will

be displayed if the new con-

numbers or "ERR", the E/PROM must be erased again, and validity of the previously entered channel information

is

in question.

29.

Install the E/PROM Module into the transceiver.

BCLO JUMPERING

The Busy Channel Lock-out feature, if programmed as previously described, prevents transmission on audible

alert

when an attempt

is

a

busy channel and can provide an

made. The standard transceiver

is

configured for BCLO by carrier detection when enabled by programming. Therefore if neither CTCSS nor CDCSS are used, no jumpers change necessary. If desired, and if CTCSS (or CDCSS)

transceiver,

a

jumper can be moved to an alternate location inside the

is

installed in the

is

transceiver to prevent transmission only when an appropriate CTCSS

tone

is

received.

The BCLO jumper positions, JP107 and JP108, are located on the Transmitter Board between the modulator (L101, L102) shield and front PC

board edge. Remove the jumper

it

into the JP108 position to

set

wire

from JP107 position and install

BCLO by CTCSS tone (or CDCSS code)

detection. Do not install jumpers in both positions.

TRANSCEIVER CALIBRATION

70-342https://manualmachine.com/442~~

SUGGESTED TEST EQUIPMENT FOR TRANSMITTER CALIBRATION

Test Instrument Instrument Capabilities Instrument Type DC Power Supply 13.8 VDC, 10 amps Power Mate BPA-20PF Wattmeter

50 watts, 136-174 MHz Bird model 43 with 50C

element and 50 ohm load

Deviation Meter 136-174 MHz.

p/o Cushman CE-31A

+/-5KHz range

Frequency Meter or 136-174 MHz p/o Cushman CE-31A or.

Frequency Counter 2.0 ppm accuracy Heath SM-4120

Audio Generator 0-10 KHz sine-wave, Heath SG-5218

0-5 Vrms output

POWER

CALIBRATION

SUPPLY

SET-UP

TRANSCEIVER CALIBRATION

The 70-342XL and 70-442XL wideband transceivers are capable of opera-

ting across realignment

frequencies. Only transmit carrier calibration such as frequency, modulation, and output power may need adjustment. The transceivers are shipped from the factory programmed with test frequencies that must be changed to customer frequencies before installation.

REALIGNMENT

sceiver tuning has been replaced. Realignment requires transceiver

operation on special frequencies, therefore they must be programmed

into the transceiver E/PROM specifically for alignment. The complete Alignment procedure can be found in the SERVICING SECTION of this manual.

a

24

MHz channel frequency spread. Therefore, receiver

is

not needed, even when reprogrammed with new customer

MAY

BE NECESSARY ONLY AFTER a component that affects tran-

-

70-342https://manualmachine.com/442~~

Error code 90, 91, 92, 93, or 94 appearing in the channel display with

-

continuous triple-beeps indicates the E/PROM module

improperly inserted, or incorrectly programmed. Check the E/PROM module or refer to the E/PROM Programming section in this service manual.

Error code 95 appearing in the channel display with

indicates the synthesizer phase-lock-loop cannot achieve lock.

defect exists and

it

must be corrected.

is

missing,

a

triple-beep

A

TRANSCEIVER CALIBRATION

The following adjustments to calibrate transmit power output, transmit carrier frequency, and transmit modulation are all that should be necessary to prepare the wide-band 70-342XL or 70-442XL transceivers for end use.

8

1. Remove the

securing screws to remove the top and bottom covers.

70-342https://manualmachine.com/442~~

2.

--Carrier Frequency Adjustment--

3. Monitor the unmodulated transmitted frequency on any channel.

4.

5.

Supply 13.6 volts DC power to transceiver 5391. Connect

9

and

[-I

(with a wattmeter) to antenna connector 5392.

Adjust REFERENCE OSCILLATOR CV701 for zero carrier frequency.

Apply 0.15 Vrms of 2500 Hz signal to the Microphone Receptacle 5393 pins 1 and 2 (5395 of the Control Head on trunk-mount transceivers). Pin 1 is signal high; pin 2 is ground.

Key the transmitter by grounding pin Receptacle, and monitor carrier modulation. Readjust applied signal level for 2.5 KHz carrier deviation (50% modulation). Adjust LlOl and L102 for maximum deviation.

If the transceiver is not equipped with a CTCSS option, skip this step. Select any channel that is programmed.for a CTCSS tone.

Remove the modulating signal and key the transmitter. While monitoring carrier modulation, adjust the TONE OUTPUT LEVEL adjustment (RV1 on the 70-2101 or 70-2102 CTCSS boards) for desired modulation level (typically 750 Hz carrier deviation).

to pin 7. Connect a resistive, 50 ohm RE load

4

of the Microphone

[+]

to

6.

--RE Power Output Adjustment--

7.

8.

9.

Calibration is complete. Normally, receiver realignment is not necessary.

Reapply the 2500

1 Vrms. Key the transmitter and adjust MODULATION LIMITING RVlOl

5

for modulation does not exceed

Set POWER SET RV502 for maximum (fully clockwise).

Select the channel that transmits the center-most TX frequency. Key the transmitter and adjust CV501 and CV504 for maximum RE

power into 50 ohms at the Antenna Connector.

Readjust POWER SET RV501 for

the Antenna Connector.

KHz carrier deviation. Vary the signal level to ensure

Hz

modulating signal, but increase its level to

KHz.

5

40

watts RF output into 50 ohms at

TRANSCEIVER CALIBRATION

TRANSMITTER AND SYNTHESIZER ADJUSTMENTS

TRANSMITTER BOARD

70-342https://manualmachine.com/442~~

RF POWER AMPLIFIER BOARD

UNDER-DASH MOUNTING (Model 70-342XL only) The 70-342XL transceiver

is

designed for use in automobiles, trucks, or other vehicles with 12 volt electrical systems. Where in the vehicle the transceiver provided

its

front panel controls

mounted does not affect

are

accessible to the operator.

its

performance,

is

Typical mounting locations are under the dashboard or next to the

driver's

The transceiver

seat.

is

housed in

a

slim,

small

package to best conform to

mounting locations. The mounting bracket slides into the transceiver

a

siderails and provides

3.25 x 7.75 inch flat surface across the

transceiver top with holes for bolting to a flat surface in the vehi-

cle.

the four

5/32" holes must be drilled in the mounting surface to accept

3/8"

screws and washers provided.

TRUNK MOUNTING (Model 70-442XL only)

is

The 70-442XL trunk mount transceiver

such

a

ceiver design,

as

a

vehicle trunk or under a seat. The operator controls

compact control head for operator access. The bulk of the trans-

is

within the separate remotely mounted unit. Because of this

its

does not have an internal speaker. Instead,

designed for remote mounting

are

in

a

separate

3.2-ohm external speaker (included with the 70-442XL package) nust be installed and connected to the Control Head.

The cable that interconnects the control head to the trunk unit

is

four meters long and flat for laying under carpeting. The cable must

not lay near hot areas (above the catalytic converter, for example) nor against sharp edges.

A

trunk unit mounting tray

is

flat tray the trunk unit

7.5 inches square and must be bolted to the surface where

will

mount. 5/32" holes must be drilled in the mount-

ing surface to accept the four

13

x 8 x 3 inch trunk unit then clips onto the tray.

A

Control Head mounting bracket.

Its

surface

is

314 inch wide and 4 inches long with two screw holes

is

provided with each transceiver. The

3/8"

screws and washers provided. The

is

provided with each transceiver.

2

inches apart. 5/32" holes must be drilled in the mounting surface of the vehicle to accept the the

318"

Control Head and bracket assembly wide, and

3

112 inches deep.

At

screws and washers provided. The

is

2 112 inches high, 4 114 inches

least

314 inch of additional depth

is

needed for the connectors that attach to the rear of the Control Head.

REMOTE SPEAKER (required and included with the 70-442XL)

As

part of the standard trunk-mount transceiver configuration (model 70-442XL), the model 70-2353 5-watt speaker connects to the Control Head Accessory Plug.

It

also can be used optionally with the 70-342XL

under-dash transceiver to substitute the transceiver internal speaker.

Its

5

112 ft. cable

is

terminated with appropriate Molex pins for

1

INSTALLATION

insertion into the trunk-mount Accessory Plug on the Control Head or the under-dash Power/Accessory Plug. The speaker housing and mounting bracket assembly

is

surface

4 1/4 x 1 114 inches, with four 3/32"

POWER REQUIREMENTS

Both the 70-342XL and 70-442XL transcqivers are designed to operate

a

from

12 volt DC, negative ground, automotive

Current drain of

of the vehicle

other

electrical

CAUTION: CHECK THE VOLTAGE SOURCE BEFORE CONNECTING THE POWER CABLE. TOO MUCH VOLTAGE (ABOVE

70-342https://manualmachine.com/442~~

is

5x5 inches square by 3 inches deep. The mounting

at

least 10 amperes should be expected. Inspection

is

recommended prior to installation.

screw

slots.

electrical

A

low battery or

system.

system defects may degrade transceiver performance.

16

VOLTS) CAN SEVERELY DAMAGE THE TRANSCEIVER.

Included with the trunk-mount transceiver

The under-dash transceiver

is

shipped with a 2

is

a

6

meter

DC power cable. Power/Accessory

cable. Each cable includes fused power leads for connection to vehi-

cle

to the negative GROUND VEHICLE. If the transceiver

electrical

system. Because the transceiver chassis

(-)

lead,

DO

NOT INSTALL THE TRANSCEIVER

is

used as a base station, the

is

connected

IN

A

POSITIVE

external AC-line-to-DC power supply must be adequately regulated and have sufficient current capacity.

ANTENNA The most important communications system component that can affect

overall performance to provide 50 ohm terminating impedance frequencies follow

its

is

manufacturer's instructions.

is

the antenna.

A

good quality antenna designed

at

appropriate transceiver

recommended. When adjusting the antenna, be sure to

A

better quality SWR

meter

should be used to accurately measure minimum reflected energy.

MICROPHONE HANGER

The hand microphone included with the transceiver has backside to three

screws

screws and three 314"

mate

with

its

hang-up clip. The clip must be mounted with

in a location convenient to the operator. Three 1/2"

screws,

each requiring a 5/64" hole,

button on

are

its

also

a

provided.

An optional microphone hanger (model 70-2195) with the CTCSS option. This hang-up box may be installed in place of the microphone clip on both

screws

provided. Wiring instructions fol3.o~ in the Power/Accessory

Plug instructions.

metallic

is

available for use

or non-metallic surfaces with two

INSTALLATION

70-342~~

UNDER - DASH CONFIGURATION

ITEM DESCRIPTION

STANDARD EQUIPMENT:

(A) (B)

(C) Dynamic Hand Microphone

(D) (E)

-

OPTIONAL ACCESSORIES (also see ACCESSORIES

(F)

(G)

Under-Dash Transceiver Under-Dash Mounting Bracket

Power/Accessory Plug and Cable, 2m Microphone Hang-up Clip with screws

Spare Fuse, 10A Mounting Hardware Kit

External Speaker, 5 watt

Microphone Hang-up Box with switch

MODEL NUMBER PART NUMBER

section)

70-2353 70-2195

:

lhlSTALLATlON

70-442XL

TRUNK - MOUNT CONFIGURATION

ITEM DESCRIPTION MODEL NUMBER PART NUMBER

STANDARD EQUIPMENT: (A) Trunk-Mount Transceiver 70-442XL (B) Trunk-Mount Mounting.Bracket 70-2206

(C)

(D) Accessory Plug 70-2222

(E) (F)

(G)

(I)

-

OPTIONAL ACCESSORY (also

(J)

Dynamic Hand Microphone 70-2301

Control Head Mounting Bracket Microphone Hang-up Clip with Speaker, Trunk Mounting Tray, with keys 70-2205 Power Plug and Calde, 6m 70-2212

Spare Fuse,

Mounr ing Hardware

Microphone Hang-up Box with switch 70-2195

5

watt

LOA

Kit

see

ACCESSORIES section):

screws

70-2353

25

UNDER-DASH POWER/ACCESSORY

PLUG

Nine-pin male Molex connector and fused, 2-meter power cable assembly, P/N 70-2211, mates to the power/accessory connector (5391) on the rear of the 70-342XL under-dash SYN-TECH transceiver. Extra pin positions are used for connection of optional devices not included with this assembly.

Optional devices can be connected to the Power/Accessory Plug by inserting Molex pins included with these devices into respective

vacant holes. Optional connections below are shown in lighter shade.

Refer to the ACCESSORIES section of this manual for pin, socket, connector body, and tool part numbers.

MUM

1

TONE

MON

0

I

TONS

OPTZOW

bU)III.IARY

COHP4ECTIQN

OP'I

10

H

BUXILJhAY

MMEGTIOH

NU.

MO.

*.+.-

2

lNSTALLAVlON

UNDER-DASH POWER CONNECTIONS

The Power/Accessory Cable connection to the vehicle

are

2

meters

and chassis ground.

long; sufficient for typical connection to a fuse block

is

equipped with two 14 gauge

electrical

system. The unterminated

wires

70-342XL

for

wires

Connect the black

vehicle--DO NOT ATTEMPT TO INSTALL THE TRANSCEIVER GROUND VEHICLE. body or chassis often provides an adequate ground if secure the

Connect the red electrical system. Because of current requirements, connection to an existing fused circuit should be avoided to prevent overload of that fuse. This penetration and transceiver defect. The connection can be made to

Ignition HOT to switch the transceiver with ignition, or to Battery HOT to enable the last-selected-channel feature of the transceiver. In the Either connection the red transceiver

EXTERNAL SPEAKER (Models 70-2352, and 70-2353):

Normally, the transceiver internal speaker ceive audio by the jumper to pins 5 and 6. If one of the MIDLAND external speakers to disable the internal speaker and the two wires from the external speaker must connect to pins Power Speaker tor (white) must be connected to pin 6, and the shield (black) to pin

wire

latter

4.

to

wire

case,

wire

A

large bolt that

it.

to the positive

has

is

wire

UNDER-DASH OPTIONAL CONNECTIONS

is

to the negative

screws

(+),

its

own in-line fuse for protection against

the transceiver must be turned off separately.

usually available in the vehicle fuse block ,if

is

terminated with an appropriate lug.

is

to be utilized, the jumper must be removed

4

to be connected,

(-)

chassis ground of the

IN

A

POSITIVE

into the

or Hot side of the vehicle

and

6.

its

input cable center conduc-

metallic

a

lug

is

connected to

NOTE: If the 70-2352

vehicle

is

used to

wire

re-

HANG-UP BOX (Model 70-2195):

If the CTCSS feature 70-2195 Microphone Hang-up contact/switch-box usually led to unmute CTCSS squelch when the microphone

center conductor of the shielded hang-up box cable connects to

3,

option board within the transceiver must also be removed.

AUXILIARY DEVICES:

Pins with certain opticnal features. Wiring details for these

found in the respective literature for the option.

the shield to pin 2. Jumper JP2 on the 70-21028 CTCSS

1

and 8 are available for auxiliary connections necessary

is

included in the transceiver, the optional

is

instal-

is

lifted. The

are

TRUNK-MOUNT POWER

AND

ACCESSORY PLUGS

The 70-342XL trunk mount SYN-TECH transceiver has two 9-pin male Molex receptacles--J391 on the trunk unit; 5394 on the Control Head. The trunk unit receptacle mates to the 70-2212 Power Cable assembly. The Power Cable includes an in-line fuse in

its

6

meter power leads and

a

jumper between pins 5 and 6 that routes speaker audio to the control head.

The 9-pin Accessory Plug connects to the rear of the control head. The speaker has Molex pins that insert into this plug. Extra pin positions

are

present for connection of the optional 70-2195 switching hang-up box (not included with the standard transceiver) for use with CTCSS or CDCSS. Two more pin positions are provided for optional auxiliary connections.

Refer to the ACCESSORIES section of this manual for pin, socket,

connector body, and tool part numbers.

OPTION

AUXILIARV

COHllECIlOW NO

OPIlOll

AUXILIARY

CONWECTlOW NO.

C

2

ACCESSORY PLUG

on the Control Head

WIC

HANO UP

UOOEL

5.2

OHM

EXTERNAL

UOOEL

70-2319 (SEE TEXT)

70-2101

BOX

SPEAKER

TONE

'

r

TOHE

I I

8JL-y;::;;;;;)

VEHICLE

10

AMPERE

(1~0 FUME

POWER PLUG

on the transceiver

INSTALLATION

TRUNK-MOUNT POWER CABLE CONNECTIONS

The 70-2212 Power Cable tion to the vehicle meters chassis ground.

long; sufficient for typical connection to a fuse block and

is

equipped with two 12

electrical

AWG

wires

system. The unterminated

70-442XL

for connec-

wires

are 6

Connect the black vehicle--DO NOT ATTEMPT TO INSTALL THE TRANSCEIVER

GROUND

body or chassis often provides an adequate ground.if secure the

Connect the red

electrical system. Because of current requirements, connection existing fused circuit should be avoided to prevent overload of that fuse. This penetration and transceiver defect. The connection can be made to Ignition HOT to switch the transceiver with ignition, or to Battery

HOT. The

transceiver, but the transceiver must be turned off separately. Either

connection

transceiver

STANDARD EXTERNAL SPEAKER (Model 70-2353):

VEHICLE.

wire

to

wire

latter

is

usually available in the vehicle fuse block if the red

wire

CONTROL HEAD ACCESSORY PLUG CONNECTIONS

The two

for insertion into positions

mates

wires

to the Control Head.

wire

A

large bolt that

it.

to the positive

has

enables the last-selected-channel feature of the

is

terminated with an appropriate lug.

of 70-2353 speaker are terminated with Molex pins

to the negative

(-)

chassis ground of the

IN

screws

(+),

its

own i-n-line fuse for protection against

4

and 6 of the Accessory Plug that

into the metallic vehicle

a

lug

or Hot side of the vehicle

A

POSITIVE

is

used to

to

wire

an

OPTIONAL 15 WATT POWER SPEAKER (Model 70-2352):

The 70-2352 power speaker has

terminated with Molex pins for inserting into the Accessory Plug. The center conductor (white) of this audio signal cable must be connected to pin 6, and the shield (black) to pin

(+)

red

that the transceiver DC power leads are connected.

OPTIONAL HANG-UP BOX (Model 70-2195):

If the CTCSS feature microphone hang-up contact/switch-box usually unmute CTCSS squelch when the microphone conductor of the shielded hang-up box cable connects to pin the shield to pin 2. Jumper JP2 on the 70-2102A CTCSS option

board within the transceiver must also be removed.

AUXILIARY DEVICES:

Pins with certain optional features. Wiring details for these are

found in the respective literature for the option.

and black

1

and 8 are available for auxiliary connections necessary

(-)

power leads that connect to the same points

is

included in the transceiver, the 70-2195

a

shielded coaxial cable that

4.

It

also has

is

installed to

is

lifted. The center

is

3,

AUTOMOTIVE RECEIVER INTERFERENCE

Occasionally, the technician who installs land-mobile radio equipment

-

is

plagued with interference originating somewhere in the automobile

that produces annoying noises through the transceiver. Interference

problems

into the transceiver, locating

it

the simplest way available.

Interference enters the transceiver two ways: by conduction or induction. Conducted interference passes through the DC power leads. Inductive interference

may be anywhere in the vehicle.

are

solved by understanding the interference and

its

source logically, then eliminating

is

radiated through the

air

from a source that

70-342https://manualmachine.com/442~~

its

path

Conducted interference

electrical

a

vehicle, current surges produce respective voltage drops across resistances. Thus, voltage transient (switching) spikes appear throughout the electrical system. Connecting the transceiver power leads to this noisy directly to the radio. Although most of the noise voltage uated by power-line filters within the radio, spikes that enough may be audible.

While interference conducted through power leads affects transceiver audio circuitry; inductive interf:erence

quencies, or even channel frequencies, and receiver. Inductive interference induces noise currents in the transceiver antenna, accessory cabling, or chassis (see Figure

A

spark frequency spectrum; thus, cally in modern vehicles, sparks ignition system, and fan motors.

Other common sources of inductive energy electronic gadgets found in modern vehicles. Their internal oscilla-

tors produce high frequency signals and radiate energy the signal frequency.

system. With many electrical devices turning on and off in

is a common source of electromagnetic energy across the radio

is

simple noise voltage present in the vehicle

electrical

system applies the noise voltage

is

atten-

are

imitates

is

an electromagnetic field that

receiver

is

demodulated by the

I.F.

1).

a

source of inductive interference. Typi-

are

found in the alternator, the

are

within

a

variety of

at

multiples of

wire

severe

fre-

THE

LOCATING

The first step toward eliminating interference

interference source and path-of-entry into the transceiver. Listening to the noise can transceiver varies with engine speed, the engine; such

Because the transceiver coupling into the transceiver (by conduction or ind.uct.ion) With

transceiver that could be radiated i.nto the receiver. Because conducted interference

all

SOURCE

tell

as

the alternator, ignition system, or tachometer.

squelch circuits open, apply an unmodulated signal to the

is

to determine the

a

lot. For example: if the noise heard in the

its

source must be related to

is

an

FM

radio, determining interference

is

easy.

strong enough to overcome any int-erference that

AUTOMOTIVE RECEIVER INTERFERENCE

70-342https://manualmachine.com/442~~

can only affect audio circuitry,

is

Another method of testing the lowest noise point in the vehicle electrical system: the battery. Because the battery acts like ducted,

ELIMINATING CONDUCTED NOISE

If there in the vehicle electrical system that needs repair. tion of this nature

creates noticeably impair vehicle operation. a

whine in the transceiver that varies in pitch with engine speed.

Also, the defective diode causes excessive arcing in the brushes,

which may produce some inductive interference.

Another possible source of conducted interference Because path-of-entry

mostly conducted, find

system for the transceiver that

ELIMINATING INDUCTIVE INTERFERENCE FROM NEARBY OSCILLATORS

will

cease.

is

a

conducted noise path, there probably

is

a defective diode in the alternator, which

a

large current ripple at alternator output but may not

a

fan also produces inductive interference, determine which

is

most predominant (see above). If the interference

to connect the power leads directly to

a

power connection point in the electrical

it

will

a

large capacitor, the noise, if con-

is

further from the fan circuit.

still

A

bad alternator diode produces

be heard if present.

is

a

defective

A

common condi-

is

a

fan motor.

item

is

If testing proves interference

of applicable inductive sources--sparks and high frequency oscillators. Modern vehicles utilize many electronic gadgets and systems

that may produce a hash or whine in the transceiver. Oscillators

within these devices, that sometimes are poorly shielded, may radiate an electromagnetic field at frequencies many multiples of the oscillator frequency.

Again, listen to the noise to learn about interfering gadget with engine speed. The interfering gadget can be isolated by temporarily removing power to

Because lead-in

is

ference

gadget itself. If so, check that the wiring to the device

the transceiver or

nected in device; close to

'sensitive'

movement.

Inductive interference may also enter through the radio receiver input--the antenna. This can be verified by substituting the antenna

and

dummy load

Without

the noise stops, interference

its

it,

more often radiated from the gadget's wiring than the

series

wires

cable with a matched dummy load and short cable (The 50 ohm

is

the receiver may become less sensitive to any signal). If

is

part of engine operation, the noise won't vary

it

wires

with the 'sensitive' lead-in wires of the interfering

its

may be identified if noise volume changes with wire

necessary to properly balance the receiver input.

act like radiating antennas, inductive inter-

its

wiring. If necessary, RF chokes can be con-

housing to kill the antenna effect. Sometimes,

is

not conducted, there are two types

its

source. Unless the

to check for absence of noise.

is

entering the antenna port.

is

not near

AUTOMOTIVE

ELECTROMAGNETIC RADIATION AT RECEIVER

RECEIVER

INTERFERENCE

MODERN ELECTRONIC DEVICE WITH INTERNAL

OSCILLATOR THAT PRODUCES

INDUCTIVE INTERFERENCE

AS RADIATING

70-342https://manualmachine.com/442~~

NOISE VOLTAGE ACROSS Rw IS

CONDUCTED DIRECTLY

INTO TRANSCEIVER

VOLTAGE PRODUCED

BY

HIGH CURRENT

SURGES THROUGH Rw.

-

12

CHOKE KILLS ANTENNA EFFECT

ELECTRICAL WIRING TO DEVICE

IGNITION

ALTERNATOR WITH BAD INTERNAL DIODE

VOLTS

H

SllRCES ARE SMOOTH ED

BATTERY CAPACITY

FIGURE

ICH CURRENT

BY

1

-

CONDUCTIVE AND INDUCTIVE INTERFERENCE

HIGY CURRENT SURGES CAIJSED

BY

DEFECTIVE

ALTERNATOR

AUTOMOTIVE RECEIVER INTERFERENCE

70-342https://manualmachine.com/442~~

If interference into the antenna originates from gadget, reduce radiation from the source with RF chokes above. Sometimes, positioning the antenna further from the gadget may

work.

ELIMINATING INDUCTIVE INTERFERENCE FROM SPARKS

Only a few areas remain in modern vehicles that produce sparks: the

alternator, ignition system, and fan motors. Sparks in modern alternators generally do not produce sufficient inductive interference

is

a

unless there produce significant conducted interference, too.

Modern vehicles use higher voltage ignition systems.

electrical leakage occurs more easily through cracks and contaminants. If the interference produces in pitch with engine speed, and seems to be the same rate spark, sparks

plug wires. Check the ignition coil, distributor cap for signs of arcing through cracks and burns or over dirt.

If the interference produces a popping sound in the transceiver at engine idle that seems to occur in time with firing of a single spark plug, and increases in rate with engine speed,

wire

spark plugs for cracks, burns, and dirt.

are

suspect. Check the distributor cap, spark plug

related defect. If so, the defect probably

a

buzz in the transceiver that increases

are

leaking to ground before distribution to the spark-

its

high voltage

a

poorly shielded

as

described

As

a

result,

as

every

wire,

a

single spark plug or

wires,

will

and

Spark plug and ignition coil

(resistive) conductors to reduce electromagnetic radiation. Older

vehicles may not be equipped applicable.

Fan motor interference from with fan speed. Badly worn brushes or bearings cause excessive sparks, therefore replacement may be necessary. capacitor can be connected to the positive lead as practical to reduce inductive interference. The capacitor body must connect securely to the grounded motor housing.

as

its

wires

such.

brushes produces a whine that varies

are

Use

made with suppressive

an ohmmeter to verify, if

A

0.1

as

close to the motor

uF coaxial

OPTIONAL ACCESSORIES

The followi.ng ark optional mobile installation accessories that are available from MIDLAND.

CONTROL CABLE ASSEMBLIES

Assemblies of cables terminated with 34-pin female connectors to connect the SYN-TECH Control Head to trunk unit.

70-342https://manualmachine.com/442~~

Flat ribbon cable, 6 meters long

Flat ribbon cable, 2 meters long Round cable, 4 meters long Round cable, 2 meters long

REMOTE SPEAKER (5 Watt) Model No. 70-2353

A

3.2 ohm, housed speaker with mounting bracket and screws to substitute the 70-342XL internal speaker (the 70-2353 speaker standard with the 70-442XL transceiver). terminated with appropriat-e Molex pins for insertion into the transceiver Power/Accessory Plug. The speaker with bracket

POWER SPEAKER (15 Watt) Model No. 70-2352

This self-contained amplified speaker

the 70-2353 Remote Speaker. nated with appropriate Molex pins to connect to the 70-342XL Power/Accessory Plug or the 70-442XL Accessory Plug. fused power leads must be connected to vehicle

ALL WEATHER SPEAKER Model No. 70-SO5

A

5

grill.

for insertion into the 70-342XL Power/Accessory Plug or the 70-

442XL Accessory Plug. The speaker inches deep, and mounts with a swivel tab.

is

watt,

Its

5x5 inches square by 3 inches deep.

Its

5.5 ft. input cable

4 ohm, outdoor speaker that can be mounted in a vehicle

8

ft. cable

is

terminated with appropriate Molex pins

is

Its

is

identically housed as

5

1/2 inches diameter, 4

Model

Model No. 70-2223 Model Model No. 70-2227

5.5 ft. cable

(+)

No. 70-2221

No. 70-2226

its

mounting

is

termi-

Its

5.5 ft.

and ground.

is

MICROPHONE HANG-UP BOX Model No. 70-2195

Detects presence of a microphone in nel monitoring by defeating CTCSS (or CDCSS) audio squelch. This accessory CTCSS (or CDCSS) feature. has 5.5 ft. cable terminated with appropriate Molex pins for insertion into the under-dash transceiver Power/Accessory Plug or the trunk-mount transceiver Accessory Plug.

HANDSET MICROPHONE Model No. 70-2311

A

handset and cradle set with instructions and appropriate Molex

wire terminations to connect to the 70-342XL Power/Accessory Plug

or the 70-442XL Accessory Plug (on the Control Head). Minor internal wiring alteration through the connector.

is

useful only if the transceiver

It

is

necessary to route audio signals

its

clip for automatic chan-

is

equipped with the

shipped with mounting screws and

OPTIONAL ACCESSORIES

70-342https://manualmachine.com/442~~

HAND

WEATHER-PROOF CONTROL HEAD Model No. 70-2210

MICROPHONE WITH DTMF PAD Model No. 70-2103A

A

hand microphone with built-in lighted four-by-four DTMF keypad (16 keys; for signaling and phone-patch

on/off switch and channel up and down

NOTE: and wired inside the transceiver or Control Head. This receptacle

is

MICROPHONE WITH DTMF PAD This complete hand microphone

it

also includes circuitry for the automatic number identifier

feature.

NOTE: and wired inside the transceiver or Control Head. This recepta-

cle

is

A

replacement for the 70-2209 SYN-TECH Control Head (with scan).

It

is

identical in size and shape, but designed for outdoor use.

Shipped with the

0-9,

A

special 6-pin microphone receptacle must be installed

included with the microphone.

A

special 6-pin microphone receptacle must be installed

included with the microphone.

*,

same

#,

and A-D) and encoder to transmit DTMF tones

access.

AND

A.N.I.

is

the

mounting hardware.

It

select

same

also has

push buttons.

Model No. 70-2104A

as

the 70-2103 except

a

keypad

SLIDE BRACKET CONVERSION KIT Model No. 70-2255

The 70-2201 under-dash Slidemount Bracket with appropriate SYNTECH siderails and hardware for mounting the 70-442XL trunk-mount

unit with the Slidemount configuration.

TRUNK-MOUNTING TRAY CONVERSION KIT Model No. 70-2256

The 70-2205 Trunk-Mount Bracket with appropriate SYN-TECH sidg-

rails

a

DESK MICROPHONE Model No. 70-2305

A

nience. Not compatable with the SYN-TECH trunk-mount transceiv-

er.

installation and appropriate wiring of the 70-K33 6-pin microphone jack kit in the transceiver.

DC POWER SUPPLY Model No. 70-2281

A

base station application. Power supply input 220 Volts AC. Output current capacity

10

LMR LOCK KIT Model No. 70-7080

A

to the SYN-TECH slide-bracket mounting.

the transceiver siderail. If the lock assembly with a trunk-mount transceiver, the transceiver must be mounted

with the 70-2201 slide-bracket (see 70-2255 Slide-Bracket Conver-

sion Kit).

and hardware for mounting the SYN-TECH under-dash unit with

the Trunk-Mount configuration.

desktop microphone with speech compressor circuitry for conve-

Intended for low ambient noise base station use. Requires

13.6 Volt DC output power supply for sourcing the 70-324XL in

is

either 110 or

is

8

Amperes continuous or

Amperes intermittent.

lock assembly and parts to add a transceiver locking mechanism

A

notch must be filed in

is

to be used

a

SERVICE

ElPROM PROGRAMMER Model No. 70-1000

The SYN-TECH transceivers contain an Erasable/Programmable Read Only Memory (E/PROM) module that holds specific customer frequen-

cies and feature selections to determine radio operation. To change this electronic information, the plug-in module must be erased with the 70-1100/1101 E/PROM Eraser and reprogrammed with the 70-1000 E/PROM Programmer. The information

the Programmer by

to the transceiver, then written into the E/PROM.

The E/PROM Programmer may be operated from a 110 Volt or 220 Volt

line. for printout of an E/PROM contents.

ElPROM ERASER Model No. 70-1100/1101

The E/PROM Module contains an integrated memory circuit that

holds electronic information until exposed to high intensity ultraviolet light. The E/PROM Eraser has for positioning eight modules under

timer

110 Volt line, the 70-1101 Eraser operates from a 220 Volt line.

EQUIPMENT

is

its

keypad, converted into binary data useful

A

provision exists to connect to the 70-1300AlB Printer

a

drawer large enough

its

ultraviolet lamp, and a

for automatic shut-off. The 70-1100 Eraser operates from

70-342https://manualmachine.com/442~~

entered into

a

E/PROM PRINTER- Model No. 70-1300A/B

This 5x7 dot-matrix impact printer connects to the 70-1000 E/PROM

a

Programmer for producing The printer uses standard 8.5-inch tractor-feed paper and operates from 110 (70-1300A) or 220 Volt (70-1300B) lines.

LMR TEST SET Model No. 70-El0

This portable test set connects to metering receptacles in MIDLAND Land-Mobile-Radio transceivers for

servicing.

DC POWER SUPPLY Model No. 70-2283

This power supply provides up to

bench testing and servicing MIDLAND Land-Mobile-Radio trans-

It

ceivers.

operates from 110 and 220 Volt lines.

printout of an E/PROM Module contents.

all

15

Amperes of

easier

alignment and

13.6

Volts DC for

SERVICE TOOLS

70-342https://manualmachine.com/442~~

TUNING TOOL: (P/N 70-156019) Green, with

one end and two hex sizes

TUNING TOOL: (P/N 70-156020)

a

end and

SPECIAL TOOL: (P/N 70-2235) Nut-driver style tool for removal of

microphone jack re.taining nuts.

CRIMPING TOOL: (P/N 70-2231) Designed for .attaching to

Molex pins and sockets that fit the SYN-TECH Power and Accessory Plugs and receptacles.

EXTRACTING TOOL: (P/N 70-2232) Designed for removing Molex pins and

sockets from the SYN-TECH Power and Accessory Plugs and receptacles.

HAND

SHEAR: (P/N 70-2230) Plier-like hand tool with blade for

cutting flat ribbon cable. Applicable use: Cutting bulk 34-conductor ribbon cable (P/N 70-034068) used to make special length SYN-TECH Control Cables that interconnect Control Heads to transcei.vers.

PRESS: (P/N 70-2229) Plier-like hand tool with a special

jaw

to press compression-fit ribbon cable connectors onto ribbon cable ends. Applicable use: Fitting 34pin SYN-TECH Control Cable connector assemblies (Model No. 70-2228) onto flat ribbon cable cut to special length.

larger blade

Black, with

at

a

small

at

the other.

a

smaller blade

the

other.

metal

blade

wire

at

one

ends,

at

REPLACEMENT POWER/ACCESSORY CONNECTOR PARTS:

*

9-pin

*

9-pin Molex

*

14-18

*

18-24

*

22-30

*

14-18

*

18-24

*

22-30

SYN-TECH CONTROL CABLE PARTS (for trunk-mount transceivers):

*

Flat Ribbon Cable, 34 cond., bulk (specify length) P/N 70-034068

*

Connector, female 34-pin double-row, insulation

displacing compression fit, with strain relief Model No. 70-2.228

Molex

AWG

AWG AWG AWG

Plug Housing w/o pins (Pwr/Accy Plug) P/N 70-151187 Receptacle Housing w/o pins (transceiver) P/N 70-159108

Male Pin

Male

Female Female Pin Female

for

Pin for Pin for

plug

for

(Molex (Molex (Molex

recept. recept. recept.

#02-09-2103) #O2-09-2118) #02-09-2143)

(Molex (Molex (Molex

#02-09-1103) #02-09-1118) #02-09-1143)

P/N 70-151187 P/N 70-151188 P/N 70-151190

P/N 70-151186 PIN 70-151189 P/N 70-151183

OPTIONAL FEATURE ADD

-

ON KITS

70-342https://manualmachine.com/442~~

Although new transceivers tures per customer specifications, most features on kit form for field modification. instructions and necessary parts for installing inside applicable transceivers.

CTCSS ENCODER Model No.. 70-2101

A

PC board assembly that generates standard subaudible CTCSS

tones (67.0 to 241.8 Hz) for transmitter modulation. Tone fre-

quency

frequencies can be different for each channel. This feature usually used in transceivers equipped with -the 70-2151 Two-Tone Sequential Decoder.

The 70-2101 Encoder mounts inside the transceiver and connects

via two connector/cable assemblies to existing receptacles. If the transceiver also contains the 70-2151 Sequential Two-Tone

Decoder, two additional

gramming and transmit modulation readjustment may be necessary.

CTCSS ENCODER/DECODER Model No. 70-21028

A

PC board assembly that encodes and decodes standard CTCSS subaudible tones (67.0 to 241.8 Hz). Tone frequencies tained in the transceiver E/PROM, thus frequencies can be differ-

ent for each channel and each mode (TX/RX). The optional 70-2195

Microphone Hang-up Box (a mobile accessory item) can be installed

to activate channel monitor automatically.

is

determined by transceiver E/PROM programming, thus

are

equipped with appropriate optional fea-

are

available in add-

All

kits are shipped with

wires

must be soldered. E/PROM repro-

are

is

con-

The 70-21028 Encoder/Decoder mounts inside the transceiver and connects via four connector/cables to existing receptacles. If

all

tone frequencies in group C, then plating cuts and component changes necessary. E/PROM reprogramming and transmit modulation readjustment

CTCSS/CDCSS ENCODER/DECODER OPTION Not field installable

Two PC board assemblies together comprise the 70-2160 option that

encodes and decodes Continuous Digital Coded Squelch data for use in DCS systems (Digital Coded Squelch to CTCSS). This option also provides CTCSS encoding and decoding. Mode of operation and standard frequencies or codes for encode and decode

channel in E/PROM programming.

Installatioc of the 70-2160 option

is

left to only MIDLAND personnel who have the necessary tools

and equipment. The 70-2160 instruction/service manual, part number 70-999420,

is

necessary.

are

in EIA standard groups A and

is

the digital complement

are

is

defined for each mode (TX or RX) of each

is

complex, therefore the task

available for the installed option.

B,

or

are

all not

OPTIONAL FEATURE ADD

2805 Hz DECODER (under-dash only) Model No. 70-2105

A

PC board assembly that decodes and notch-filters received 2805 Hz tones for operation with 2805 Hz signaling systems. A 2 ampere maximum ground sinking output for connected through the transceiver power connector. Compatibility

of this kit 2115 kit

The decoder PC board mounts inside the transceiver and several

wires must be soldered. An on-channel signal with continuous 2805 Hz tone modulation and an AC voltmeter alignment.

DTMF DECODER Model No. 70-21068

A

PC board assembly that decodes received DTMF tone sequences for station calling and initiates can distinguish a Primary sequence and a Secondary sequence, plus

a

group pair. Two outputs for controlling devices external to the transceiver provides ampere maximum sink to ground.

is

limited to only under-dash transceivers. The 70-

is

the trunk-mount complement.

call

are

response from receipt of 5 seconds of the

provided

a

1

ampere maximum sink to ground; the other

at

-

ON KITS

a

vehicle horn relay can be

are

an

acknowledge tone. This decoder

the transceiver power connector: one

70-342https://manualmachine.com/442~~

necessary for

"*I1

a

,

tone

.25

The 70-2106A installed in

70-2195 Microphone Hang-up Box

The decoder mounts inside the transceiver. The transceiver front

panel must be altered and several wires must be soldered. tone generator and an RF signal generator programming. Transmitter modulation may need readjustment.

TUNABLE VOICE SCRAMBLER Model No. 70-2107A

This PC board assembly scrambles and descrambles speech by fre-

quency inversion for communications privacy. The scrambler tunable for references between 2700 Hz to 3600 Hz.

The scrambler mounts inside the transceiver and several wires must be soldered. The 70-442XL Control Head may also require

wiring. An audio frequency counter alignment and transmitter modulation

BURST-TONE ENCODER Model No. 70-2109

This PC board assembly produces

PTT for transmission. The tone burst between 0.2 and 3000 Hz.

is

compatible only with under-dash transceivers. If

a

transceiver equipped with the scan feature, the

is

required.

are

needed for decoder

is

needed for scrambler

will

a

burst of audio tone signal upon

1

second at a preset frequency between 700 and

need readjustment.

is

for a preset duration

A

DTMF

is

The encoder mounts inside the transceiver, and several connec-

tions must be soldered. Encoder alignment requires counter and measurement of transmit modulation.

a

frequency

OPTIONAL

MULTI BURST-TONE ENCODER Model No. 70-2110

For multiple repeater access, this encoder produces a burst of audio tone signal upon PTT that is transmitted. The tone burst is for a preset duration between 0.3 and

tone frequencies are selectable by a rotary switch, but all ten must be either between 300 and 1600 Hz, or between Hz. The encoder is a housed unit that mounts near the transceiver (or the Control Head of trunk-mount transceivers) where accessible to the operator.

Four wires must be connected from the encoder unit to the transceiver Power/Accessory Plug (or the Control Head Accessory Plug). Some rewiring inside the transceiver (and the Control Head) is necessary to accommodate encoder connections. If either the 702195 Hang-Up Box or the 70-2353 External Speaker are connected to the Plug, the Plug must also be rewired to open pin positions.

Encoder alignment requires a frequency counter and measurement of

transmit modulation.

2805 Hz DECODER (trunk-mount only) Model No. 70-2115

Decoder circuitry is identical to the 70-2105 2805Hz Decoder.

Only installation parts and instructions are different. This kit

is compatible only with the 70-442XL trunk-mount transceiver.

The 70-2105 2805Hz kit is the under-dash complement.

FEATURE

ADD

-

ON KITS

70-342https://manualmachine.com/442~~

3

seconds. Up to ten

800

and 3500

The decoder PC board mounts inside the transceiver and several wires must be soldered inside both the transceiver and Control Head. An on-channel signal with continuous 2805 Hz tone modula-

tion and an AC voltmeter are necessary for alignment.

2.0 or 2.5 ppm OSCILLATOR CONVERSION Model Nos. 70-2124/2125 These kits contain the necessary components for replacing the

transceiver master oscillator crystal to improve the oscillator frequency stability from 5 ppm to 2.0 ppm (70-2124) or to 2.5 ppm (70-2125). Frequency realignment is necessary.

TWO-TONE SEQUENTIAL DECODER Model No. 70-2151/2152

A PC board assembly that decodes sequential two-tone calling signals between 280 and 3500 Hz (including Group call). Output is an alert tone to the transceiver speaker, plus two relays are

energized to control external devices., Relay contact connection

is limited by availability of only two transceiver Power/ Accessory connector pins and ground. Relay closure is momentary or latched p'er jumper selection and contact current capacity of each is 1 ampere maximum.

The 70-2151 Decoder kit contains parts to install the feature

into the under-dash SYN-TECH transceivers; the 70-2152 kit con-

tains parts to install into trunk-mount transceivers and Control Heads.

The decoder mounts inside the transceiver and requires front

panel or Control Head alteration. Internal wiring is to existing

connectors. Alignment requires at least an audio tone generator and AC voltmeter, or an audio frequency counter.

OPTIONAL

SELECTIVE SIGNALING DECODER Models No. 70-2153/2154

A

PC

and 1200 Hz (including Group call). Output

the transceiver speaker, plus two relays are energized to control external devices. Relay contact connection bility of only two transceiver Power/Accessory connector pins and ground. Relay closure tion and contact current capacity of each

The 70-2153 Decoder kit contains parts to install the feature into the under-dash SYN-TECH transceivers; the 70-2154 kit contains parts to install into trunk-mount transceivers and Control Heads.

The decoder PC board mounts inside the transceiver and requires

front panel or Control Head alteration. Internal wiring existing connectors. Alignment requires an audio tone generator and AC voltmeter or an audio frequency counter, and measurement of transmit modulation.

HIGH-SIDE SECOND LOCAL OSCILLATOR CONVERSION Model No. 70-2164

If the transceiver

is

installation of this kit may eliminate receiver response to the

interfering signal. This kit replaces the 20.945MHz second oscillator crystal with

injection from standard low-side to high-side, thus shifting the

spurious response frequencies that

I.F. image. This kit

ference signals, or their harmonics, mix to produce: Fc (channel

frequency) minus 910KHz (2x 2nd I.F.); or Fc minus 41.89 MHz (2x

2nd L.O.). After the kit

response frequencies

change to: Fc plus 910 KHz; and Fc minus 43.71MHz.

FEATURE

board assembly that decodes 2+2 tone signaling between 280

afflicted by a high level RF signal at certain frequencies,

ADD

is

installed in an fixed environment where

is

are

-

ON

is

momentary or latched per jumper selec-

a

21.855MHz crystal which changes second

effective only if one or more the inter-

is

installed,

the

same

KITS

is

an

is

limited by availa-

is

1

ampere maximum.

are

a

function of the second

all

receiver spurious

except the above formulated two

70-342https://manualmachine.com/442~~

alert

tone to

is

to

it

HIGH-SIDE FIRST INJECTION MODIFICATION Not field installable

If the transceiver

is

afflicted by a high level RF signal installation of this kit may eliminate receiver response to the interfering signal. This modification changes the first injection frequency from standard low-side to high-side, thus shifting the spurious response frequencies that are a function of the first I.F. image. This modification

more the interference signals, or their harmonics, mix to pro-

duce: Fc (channel frequency) minus 42.8 MHz (2x

minus 41.89 MHz (2x 2nd L.O.). After the kit

receiver spurious response frequencies above formulated two change to: Fc plus 42.8MHz; and Fc minus

43.71MHz. This modification

MIDLAND personnel

is

installed in an fixed environment where

at

certain frequencies,

is

effective only if one or

1st

is

installed,

are

the same except the

is

complex, therefore the task

who have the

necessary tools and equipment.

is

it

I.F.); or Fc

all

left to only

OPTIONAL

CTCSS KIT REVERSE BURST MODIFICATION Model No. 70-2199

A

PC board assembly that modifies the 70-21028 CTCSS Encoder/ Decoder to cause an out-of-phase burst of CTCSS tone of transmission (after PTT release). The reverse burst to stop vibrations in old-style mechanically resonant tone decoder reeds, thereby shortening the "squelch receiver.

FEATURE

ADD

-

ON

KITS

tail"

at

70-342https://manualmachine.com/442~~

at

the

is

the listening

tail

used

The modifier kit

wires

Encode/Decoder. Transmit modulation may require readjustment.

PARALLEL CONTROL HEAD ADAPTOR Model No. 70-2207

An adaptor cable to connect two Control Heads to one trunk-mount

transceiver. This adaptor

Control Cable to parallel

MICROPROCESSOR KEEP-ALIVE KIT Model No. 70-2215

Wire

the vehicle battery to the transceiver microprocessor in installations where the transceiver DC power connections to the vehicle ignition circuit. With microprocessor internal memory always active, nels

The fused B+ wire included in this kit must be added to the

transceiver Power/~ccessory Plug and connected to the vehicle battery or

added.

SYN-TECH TRUNK-MOUNT TO UNDER-DASH CONVERSION Model No. 70-2251

A

kit containing the SYN-TECH under-dash front panel assembly and appropriate under-dash mounting hardware to convert the transceiver configuration.

must be soldered to the transceiver and the 70-2102A

and components to provide constant low-current DC power from

are

maintained while the vehicle ignition

a

non-switched circuit. Other components must also be

is

installed inside the transceiver and several

is

a

"Y"

cable that installs in the

all

Control Head connections.

last

are

selected operating and Priority chan-

is

off.

connected

SYN-TECH UNDER-DASH TO TRUNK-MOUNT CONVERSION Model No. 70-2252

A

kit containing the Trunk-mount transceiver front assembly, Control Head, and appropriate trunk-mount hardware and sories to convert the transceiver configuration.

TALK-AROUND PUSH BUTTON KIT (for under-dash.units) Model No. 70-2815

A

PC board and parts to provide an additional switch on the transceiver front panel that, when pressed while (transmit frequency and receive frequency different for communications through to operate in simplex mode (transmit and receive frequencies identical). The 70-2815 kit transceivers only. The 70-2816 kit ment.

A

front panel push button function face plate. Several soldered connections must be made.

a

repeater)

is

selected, causes the transceiver

is

compatible to the under-dash

is

the trunk-mount comple-

is

changed by replacing the

a

duplex channel

acces-

OPTIONAL

FEATURE

ADD

-

ON

KITS

70-342https://manualmachine.com/442~~

TALK-AROUND PUSH BUTTON

Same as the 70-2815 kit for under-dash SYN-TECH transceivers, except some parts are different for compatibility to trunk-mount transceivers.

6-PIN MICROPHONE JACK REPLACEMENT Model No. 70-K33

This kit contains a 6-pin jack and parts to replace the 4-pin microphone jack in either the under-dash transceiver (J393), or the trunk-mount transceiver Control Head (5395). The 6-pin jack is necessary for connection with the 70-2305 Desk Microphone. is also needed for connection of the 70-2103A/70-2104A DTMF Encoding Microphones, but is included with each of them.

Jack wiring inside the transceiver for the Desk Microphone is not the same as for the DTMF Encoder Microphones. The 70-2235 Jack Removal Tool makes removal of the front jack retaining nut easy.

KIT

(for trunk-mount units) Model No. 70-2816

It

SERVICING

GENERAL TROUBLESHOOTING CHART

70-342https://manualmachine.com/442~~

Distorted

'~r

ansmit and Receive

No Transmit Transmit

OK,

Cannot Change

Audio Audio

C

hanne

1

s

!I

Confirm Scan Programmed in

E/PROM

and Scan kit properly installed

See Modulator Trouble-

shooting Chart

I

Receiver

is

off

Freauencv

I

Substitute

Low Transmitter

-

Voltage Regulators

E/PROM

blodule

I

blake sure E/PRObl Flodule

is

correctly inserted or substitute known good module

Receiver is Dead

Error Code 90

-

Substitute

E/

PROM

-

A

-

Transmit and Rcceivc

OK

Output Power

OK

or 94

is

Displayed

Module

Same lndication

L

A

Display blank or incorrect

Substitute

Same

Indication

Same Same

lndication

No Output Power

E

/

PROM

Module

Main

VCO

out of lock

See Transmitter Trouble-

-shooting Chart

Check Receiver

Chcck IC303 +8VDC Supply

Squelch Operation

OK

See

CPU/PLL

Transmitter Of

A

Troubleshooting

:

-

Check IC 301

L

A

Frequency Chart

-

and IC 302

1

Same Indication

range. Check

VCO

(TP701) or substitute E/PROM Module

OK

Error 91, 92, 93 or 94 are

CPU

Error Codes

I

Rcceiver Signal

1)

I

storted

Same

lndication

grammed into E/Prom

See Receiver

Transmit, No RED Transmit LED

-

--

Confirm Transmit programmed

OK

Check 4301

for selected channel

-

and 4302

-

Receive

OK

but Cannot

Troubleshooting Chart

g

CPU/PLL TROUBLESHOOTING CHART

70-342https://manualmachine.com/442~~

Receiver off

Displayed

Error

Code

94

is

Displavcd and 93 are displayed

Substitute

EIPROM

Substitute E/PROM

Check for

2.5MHz

Module

at

IC702

12

-

OK

pins

1,

6 & 7 bv

switching

+

Check

for

pulses

on IC701 None Check for pulses at IC901

No

Pulses

Check for pulses input on 1~901

T.7~2 on TP701 Q703, 5.12

MHz

pins 1,40,41,42 by switch-

.

pins 1.4,5,6,7,13,14 & 15 by

Check

CMlOl

from Rx to Tx to

Rx

ing from

RX

to TX to

RX

at

pin41 switching from

RX

to TX to RX

OK

No Pulses at Pins

All

are

?,

40 or 42

Hi

or Lo

\I

Dl07 anode high

r

1

Turn radio off and momen- Substitute ElPROM tarily ground pin 21 of

-

Module

IC901,then turn

thd

radio o

All

are

I

All

are

still

-

Problem

is

HI

or Lo

T

Hi

or 1.0

Check for Loc. Osc.

No Transmit,

Check for pulses on IC901

-

1

Check for Pulses on IC

[check for +5VDC on pin 19, 20

1

-

pins 32.33,34,35,36,37

&

)

701 pins 4 & 5

and 21 of IC 901,

OV

on pin 15

38 by switching from

RX

to TX to

RX

OK

Check for RF at VCO

11

oscillator Q707,

Check 800 KHz clock If radio has BCLO check squelch;

(RX

LO) at 5365

IC704 Buffer 4708

on IC901 pins 17

&

18

then check if pin 28of IC901

is

Lo.

A

t

OK

I

OK

Check the DC Amp. 4704,

Shooting Chart Check if pin 30 of IC901 goes

0705, 4706 IC701,pin

11

Check IC401 & 1~402 OK

Hi

in Transmit Mode

Lo Transmit or Receive

-

Voltage Regulators

Recheck IC901 input control pins

N~~~

Check for pulses on IC901

4

Lo Receiver in Standby ?lode

pins 10,11,22,23,23

&

25

Pin 6

Hi

Main

VCO

unlock from IC701 pin 10 cceive OK but cannot transmit,

by changing channels Pin 8

Hi

Scan Button Out ed tranqmi

f

I.FD

not on

Pin 9

Hi

Primary Button Out

OK

Pln 26

Hi

Channel Switch in neutral position

Check for pulse on IC301 and

None

rl

Pin 27

Hi

Channel Switch

in

neutral position

Same

Check IC402 IC302 on pins 1,2,5,6 & 7 Pin 28 Lo Receiver in Standby Mode

by changing channels Pin 29

Hi

Receiver in Standby Mode

1

Pin 30 Lo Receiver in Standby Mode

I

Pin 31 Lo Receiver in Standby Mode

Confirm that IC901 pin 26

OK

Confirm that IC901 pin 8 goes low

Substitute ElPROM

goes low in

DN

Channel and

4

in SCAN mode and pin 9 goes low

Module

pin 27 goes .low in Up Channel

in

PRI

mode. Sq. Sig

is

Lo

at

4.

1

I

Check IC303 +BVDC

SUPP~V

1

I

1

I

1

Receive Mode

1

I

Transmit ~odel 1 Transmit & Receive

OK~

1

Substitute ElPROM Transmit and Receive OK

Module Cannot change channel

Check Receiver

Display

is

Blank or

1

Q7~;;cBasc is

I

1

Q40;v;fse

is

1

incorrect

1

I

Transmit and Receive

OK,

No Scan

I

Fold

Out

-

Pl-3

n

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RECEIVER TROUBLESHOOTING CHART

70-342https://manualmachine.com/442~~

Fold

Out

-1C401

defective or short

on

RX

+8VDC line

1.7V

Bad Check CM202

NO

Dead

.

OV

_OK

Check Main

VCO

Receiver Problem

A

.

pin 1 for

-

TP701 voltage

-

(1.5-SV) Slgnal

-RX

ov

0

K

(OV or 6.5V)

Check IC401

6

+8VDC

8V 0.7V

No

Check. IC401 Pin

5

\'

Check 4203 and alignment

A

of L209 and L210

A

\I

Weak Signal

Check IC251,X251 and

'

Squelch

Distorted

Slgnal

I

Check IC252 Audio

1

Re Cer to CPU/PLL

Replace

11

alignment of L252 -Output

IC

.Troubleshooting

Chart

4403

Check TP752 for Receiver

OK

0

K

Tracking Control Voltage 95 Error Code and Adjust RV752.

C

(OV-9V)

Check Q201,Q202,Q251,FL251,

Check Squelch IC251 pins 10,11,

12,13

&

14. Q252,D252 and D253

-

OK

Check

4259,9260,

-

Q261,D259,

dnd

D260

-

FL252,FL253 and alignment of L201,L202,L203,L204,

L205,L206,L208 and L251.

COMPONENT REPLACEMENT

CHIP COMPONENT IDENTIFICATION

70-342https://manualmachine.com/442~~

CHIP CAPACITORS:

and marked with one alphabetical character followed by a numerical multiplier. Bars above, below, or beside these characters define

temperature characteristic.

ALPHABET CHARACTER

A

B

C D E F

G

H

J

K L M N

P

R

S

NUMERICAL

VALUE

1.0

1.1

1.2

1.3

1.5

1.6

1.8

2.0

2.2

2.4

2.7

3.0

3.3

3.6

4.3

4.7

Chip capacitors typically are brown, green or white

ALPHABET CHARACTER

T

U

V W

X Y Z

a

b

d

e

f m n t

Y

NUMERICAL

VALUE

5.1

5.6

6.2

6.8

7.5

8.2

9.1

2.5

3.5

4.0

4.5

5.0

6.0

7.0

8.0

9.0

NUMERICAL CHARACTER

0

1 2 3 4 5 8 9

MULTIPLIER

VALUE

1.0

10 100

1000 10,000

100,000

0.01

0.1

TEMP. COEFF.

(PPM/"C)

NPO

N150

N220

N330

N470

N750

N1500

+350

-1000

+20%

-20%

+80%

-20%

BAR

LOCATION

fi

A1

AT

-

A

1

-

A

I

A

1

A

-

1

A1

A11

--

A

1

-

Example:

CHIP RESISTORS:

white with blue value markings. Resistance in ohms can be determined from value markings as follows:

1st two digits

3rd digit

Example:

A1

marking indicates a

A

=

1.0,

--

125 = 12

1 = x10,

Chip resistors used in the

--

significant numerals

amount of following zeros

&

00000

10

pF

two bars above

=

1,200000

ohms

NPO

capacitor.

=

SYN-TECH

(00

=

1.2

NPO

to

99)

megohm

typically are

COMPONENT REPLACEMENT

REPLACING COMPONENTS WITH LEADS

STATIC POTENTIALS

70-342https://manualmachine.com/442~~

Many of the components utilized in the transceiver

are

higher voltages whether they

in or out of

are

susceptible to

a

circuit. Before

handling and soldering components and circuit boards, take measures to

avoid

static

or AC-line potentials.

It

is

best to use

a

grounded

soldering iron to prevent AC-line and static 'hot' soldering tips.

Because the objects that touch the circuitry during the component

a

replacement process each carry way to alleviate risk of component damage from make

soldering iron

all

these contacting objects carry the

is

grounded, everything

bench, the equipment being worked on, and you. There usually isn't need to

wire

yourself to your bench unless you work on carpeting on dry-air days. Just make sure you and the grounded work the

DESOLDERING

Extreme that feed through

same

potential by touching bench ground when sitting down.

AND

RESOLDERING

care

must be exercised when raplacing components with leads

a

PC board. The copper plating on both sides of the

different static potential, the only

same

else

static

potential. Since the

must be grounded--the

discharge

is

to

a

area

are at

printed circuit board and inside component lead holes easily separates

and tears from the PC board when heated.

A

solder suction tool or braided desoldering wick can be used to

a

remove solder from component leads, one at

time. Solder must be removed carefully and thoroughly so that the IC can be pulled without resistance. Cutting the defective component away from

its

leads first

makes removal of the leads and solder easier.

Before installing

a

new component, remove

all

solder from lead holes and assure proper orientation of the device. Always inspect old part leads for any feed-through plating rings that may have been pulled out of holes. The plating may have completed the corresponding lead of the new component runners on both sides of PC board

TORN-OUT HOLE PLATING

SOLDER SIDE PLATING RUNNER THAT WAS CON-

NECTED TO COMPONENT

SIDE RUNNER OUT HOLE PLATING.

BY

TORN-

FEED-THROUGH PLATING

as

shown below.

a

circuit. If so, make sure

is

soldered to plating

COMPONENT SIDE PLATING RUNNER. SOLDER COMPONENT .LEAD TO BOTH THIS RUNNER AND SOLDER SIDE RUNNER.

COMPONENT REPLACEMENT

70-342https://manualmachine.com/442~~

CHIP CAPACITOR

The following describes how to remove a chip component and affix one with maximum solder-bond success.

its

tip temperature between

Because of thermal

stresses

AND

RESISTOR REPLACEMENT

a

new

A

soldering iron that regulates

600-700

degrees Fahrenheit

is

required.

involved, no chip component can be unsol-

dered, then resoldered, without damage. Never reuse chip components.

Also, do not apply heat to pads or components any longer than neces-

sary--chip components burn easily.

CAUTION

:

Application of too much solder ,can create solder bridges

between PC patterns under the soldered component and around the pad.

1.

Place

melt

1

and

a

solder iron tip directly on the defective component to

the glue under the component and solder

2.

Remove component with tweezers or longnose pliers.

as

shown in Figures

Discard the component.

2.

3.

FIG..

+I

FIG..

+2

Completely remove old solder, old glue, and any other contami-

nants from the

area

dering wick also works

Apply a in Figure

small

3.

amount of fresh solder to the clean PC pad as shown

with a desoldering tool and alcohol. Desol-

well.

L

FIG.

+3

L

COMPONENT REPLACEMENT

CHIP REPLACEMENT (continued)

'

4.

Place component and briefly heat the new solder and pad while holding the component with tweezers--do not touch the new compo-

nent with the iron. Only heated solder should touch the compo-

a

nent to make

light 'tack' bond to

FIG.

+4

it.

See Figure

~O-~~ZXL/~~ZXL

4.

5.

With one component end tacked to hold

it,

the other end can be

soldered. Carefully apply heat to the PC pad while adding only enough fresh solder to produce not apply too much solder, otherwise

a

clean fillet as in Figure 5--do

it

may flow underneath and short the pads together. Let the hot solder flow onto the component--never touch the component with the iron. Repeat to finish the other end of the component. Solder must adhere to lic end-surfaces on both ends of component

as

in Figure

all

6.

metal-

CAUTION: Never apply an iron tip directly to a chip component. Too much heat and contamination

will

break down the metallic film on

component ends resulting in loss of connection to one or more capaci-

tor wafers. If satisfactory solder adhesion does not occur, the metallic end surface has been damaged and the chip component should be replaced again. More soldering

will

only damage the component

further.

Am-

.

...,

..:'

.

-,.

-.:.

:.::.

-..:>,.

COMPLETE

The 70-342XL and 70-442XL wideband transceivers are capable of operating over a 24 MHz channel frequency spread without retuning. Main-

tenance calibration described previously is sufficient alignment in most cases. The following procedure is for realignment of the transceiver upon replacement of a component that may affect alignment. This realignment procedure requires the presence of test channel

frequencies in the E/PROM, therefore E/PROM reprogramming is necessary

(see the E/PROM Programming section).

Test Instrument Instrument Capabilities Instrument Type

ALIGNMENT

SUGGESTED TEST EQUIPMENT

70-342https://manualmachine.com/442~~

DC Power Supply 13.8 VDC, 10 amps

Wattmeter 50 watts, 136-174 MHz

&

Digital Multimeter 0.1 to 20 volts DC

Distortion Analyzer lKBz,

Speaker Load 3.2 ohms, 10 watt

RE Signal Generator 136-174 MHz range.

0.1-1KuV output, FM modulated

Deviation Meter 136-174 MHz.

+/-5KHz range

Frequency Meter or 136-174 MHz

Frequency Counter 2.0 ppm accuracy

Audio Generator 0-10 KHz sine-wave,

0-5 Vrms output

<

2% range

AC

Power Mate BPA-20PF

Bird model 43 with 50C

element and 50 ohm load

B-K 2810

Cushman CE-31A

p/o Cushman CE-31A

p/o Cushman CE-31A or

Heath SM-4120

Heath SG-5218

For Factory Presets alignment:

RF Probe for DVM .25-30 Vrms input

HP 11096B or

Fluke 83RF

COMPLETE ALIGNMENT

70-342https://manualmachine.com/44zx~

TRANSMITTER AND SYNTHESIZER ALIGNMENT SET-UP

RECEIVER ALIGNMENT SET-UP

54

COMPLETE ALIGNMENT

70-342https://manualmachine.com/442~~

* * *

Error code 90, 91, 92, 93, and with continuous triple-beeps indicates the E/PROM module is missing,

improperly inserted, or incorrectly programmed. Check the E/PROM module or refer to the E/PROM Programming section in this service manual.

Error code 95. appearing in the channel display with a triple-beep

indicates the synthesizer phase-lock-loop cannot achieve lock. defect is present and must be corrected.

THIS PROCEDURE IS ONLY NECESSARY if alignment has been changed by component change or tampering. THE E/PROM MUST BE REPROGRAMMED for

special test frequencies.

--

Set-Up

--

*

ERROR CODES

94

appearing in the channel display

REALIGNMENT PROCEDURE

* * *

*

A

1. Remove the 8 securing screws to remove the top and bottom covers.

2. Remove the E/PROM Module. Replace it with another E/PROM Module that has been programmed with the following channels. INCLUDE

THE CENTER FREQUENCIES as described in the E/PROM Programming

section.

A-BAND XCVR

-

RX 156.00 MHz

Test Channel Test Channel

Test Channel

Test Channel Test Channel

Test Channel

3. Turn the volume control to a mid position and the squelch control

fully counterclockwise.

4.

Supply 13.6 volts DC power to transceiver 5391. Connect pin 9 and

(with a wattmeter) to antenna connector 5392.

1

-

TX 156.00 MHz

1

-

RX 148.00 MHz

2

-

TX

2

-

RX 136.00 MHz

3

-

3

TX

[-I

to pin 7. Connect a resistive, 50 ohm RF load

148.00 MHz

135.00 MHz

B-BAND XCVR

174.00 MHz

160.00 MHz

150.00 MHz

[+I

to

COMPLETE

TRANSMITTER BOARD

.

ALIGNMENT

TRANSMITTER AND SYNTHESIZER ADJUSTMENTS

70-342https://manualmachine.com/442~~

TP70l

0

,702

@

,704

TP762 @CVlO2

RV7.2

@o@Rv751

fi

G

'~~751

,107

0

E@

TPlOl

-

RVlO2

@ @

RVIO1

COMPLETE

SYNTHESIZER ALIGNMENT

ALIGNMENT

70-342https://manualmachine.com/442~~

5.

6.

7. Select Test Channel 2. While in receive mode, adjust MAIN VCO

8.

--Electronic Tuning Tracking--

9.

10. Select Test Channel 1 and key the transmitter. Adjust TX

TRANSMITTER ALIGNMENT

Select Test Channel 1. Activate the transmit mode by shorting MICROPHONE 5393 (or 5395 of the Control Head) pins 2 and Adjust MAIN VCO RESONANCE L702 for 5.5 volts DC on MAIN VCO STEERING TP101.

Continue transmitting on Test Channel 1. Adjust L107 for 5.5

volts DC on TX VCO STEERING TP101.

RESONANCE L704 for 5.5 volts DC on MAIN VCO STEERING TP701. Select Test Channel

least 1.0 volt DC in receive niode, repeat steps 5 through

With the transceiver set to receive Test Channel 3, adjust RX TRACKING RV752 for 1.0 volt DC on TP752.

TRACKING RV751 for

3.

If MAIN VCO STEERING TP701 is not at

9.0

volts DC on TP751.

4.

8.

11. Select Test Channel 3 and key the transmitter. Adjust CV102 for a minimum DC voltage on CMlOl pin 2 (TX Preamplifier Collector Current).

12. Align carrier frequency, modulation, and power output as instructed in the Maintenance Calibration procedure. Use Test

Channel

13. Apply 0.15 Vrms of pins 1 and 2 (5395 on the trunk-mount Control Head). Pin 1 is signal high; pin

MIC SENSITIVITY RV102 for carrier (excluding CTCSS deviation, if present).

3

for RF Output Power Ad,justment.

1

KHz signal to the Microphone Receptacle 5393

2

is ground. Key the transmitter, then adjust

+/-

2.5 KHz deviation of transmitted

COMPLETE ALIGNMENT

RECEIVER ADJUSTMENTS

RECEIVER BOARD

70-342https://manualmachine.com/442~~

-.

COMPLETE ALIGNMENT

RECEIVER ALIGNMENT

All audio measurements in the following steps are taken across an external 3.2 ohm, 10 watt resistor connected to pins Power/Accessory Plug P393 (or the Power Plug 5391 on trunk-mount units) in place of the wire jumper in pins 5 and speaker will be disabled.

14. Select Test Channel 3 (lowest test frequency). Adjust L209 and

L210 for maximum DC voltage on Injection Metering Point CM202

1.

15. With Test Channel 3 selected, apply sufficient unmodulated, on-

channel RF signal to the antenna connector to maintain approximately 20 to 30 dB quieting. Adjust L201, L202, L204, L205, and L206 for maximum quieting indication (peak positive voltage) at CM202 pin

2.

6

4

.

70-342https://manualmachine.com/442~~

and 6 of the

The internal

16. Apply 1 mV of modulated (1 channel RF signal to the 50-ohm antenna connector. Adjust

-

17. Apply enough modulated

18. Apply 1 mV modulated (1

19.

20. Apply unmodulated on-channel RF signal to the 50-ohm antenna

DETECTOR L252 for maximum audio output.

channel carrier to maintain 12 to 15 dB SINAD. Adjust L208 and L251 for best SINAD.

carrier. Readjust L208 and L251 for minimum receive audio distortion. NOTE: If a distortion analyzer is not available, this step may be deleted--although distortion specifications may not be met.

Set the front panel SQUELCH control to maximum (full clockwise).

Set SQUELCH RANGE RV251 fully counterclockwise.

connector at a level equal to the desired tight squelch

sensitivity (usually 1.5 microvolts). Adjust SQUELCH RANGE RV251

clockwise just until squelch opens (audio on).

(1

KHz

tone, +/-3

KHz

deviation) on-

KHz

deviation) on-

KHz

deviation) on-channel

21. Apply modulated signal to the antenna connector. Turn the front panel VOLUME control to maximum and adjust audio output power (below

DO NOT ADJUST THE FOLLOWING coils unless components connected to them have been changed, or the coils themselves have been replaced, or they have been accidently turned. Undisturbed, their factory settings should provide optimum performance for the life of the transceiver.

If any of these coils need alignment, the following steps require direct measurement of RF levels in circuitry. These measurements can only be taken with an RF probe that has

tip Suggested Equipment List for recommendation.

to

convert RF signal to DC for measurement with

(1

KHz

tone,

+/-3KHz

MAXIMUM

5

watts) into the 3.2 ohm audio load.

FACTORY PRESETS

deviation) on-channel RF

VOLUME RV252 for desired

a

diode close to the probing

a

DVM.

See the

**

All

adjustments following must be made with the Test E/PROM

installed in the transceiver and with Test Channel 2 selected.

L707, L708, L709 (Main VCO) Adjust L709 for maximum Injection RF

at

signal level RF signal level

L110, L111, L112 (Transmit VCO) With the transmitt.er keyed, adjust LllO and Llll for maximum transmit RF signal level

(probe the component-side runner from pin of C176). Adjust L112 for

(probe

L118

keyed,

a

wire

(Down-converted

adjust L118 for

5365. Adjust L707 and L708 for maximum PLL feedback

at

IC703 pin 2.

at

IC104 pin

11

to the feed-through pad

a

maximum PLL feedback signal level on L117

loop of the coil).

transmit

a

maximum RF signal level

PLL feedback) With the transmitter

at

IC106

pin 14.

11

CIRCUIT ANALYSIS

The 70-342XL and 70-442XL transceivers contain three major PC boards:

/

the Transmitter Board, the Receiver Board, and the

The Transmitter Board

transmitter, frequency synthesizer, and microprocessor control circuits.

MICROPROCESSOR CONTROL CIRCUITRY

-

TRANSMITTER

is

the subject of this section and contains

BOARD

RF

Power Amplifier.

70-342~~1442~~

Activity of the entire transceiver IC901 via control signal interconnects. Microprocessor activity in turn based on an internal 800 form step-by-step instructions from an internal tions cause the microprocessor to sample logic high and low voltages

on

pins with speed such that response

Various interconnections to IC901 carry logic high and low potentials

as

microprocessor. These status and control interconnects are routed throughout the transceiver to manipulate CESSOR (IC901) PINOUTS in this section for details of microprocessor pins and functions.

Note that certain port interconnects are both and input and an output.

This

is

sor and transceiver control circuitry connected to the same point. another instance the microprocessor applies a logic potential to the control circuitry.

These information gathering (status) and manipulating (control) inter-

connects are the media of the data moving operation of the microprocessor, therefore they connections to the microprocessor are supportive to the microprocessor itself and

is

a result of

its

input pins and apply appropriate logic voltages

status input to the microprocessor and control output from the

is

a

time

applied from transceiver status circuitry to both the microproces-

are

sharing situation.

identified respectively.

its

own internal activity. Repetitive operations

KHz

oscillator continuously access and per-

are'

identified hereinafter as ports. Other

is

manipulated by microprocessor

list.

seems

At

instantaneous.

its

operation. See MICROPRO-

one instance a logic potential

The instruc-

at

its

output

At

E/PROM READ

A

table of radio operating parameters and channel frequencies contained in E/PROM IC951. The parameter data 'words' in the form of on or off

highs and lows to the microprocessor; one 'word' at a

needed. The microprocessor reads each 8-bit word by calling, or

addressing, the apply respective logic potentials at eight E/PROM outputs for transfer

to the microprocessor.

cell

states

cells

within addressable locations

in groups of eight. Once addressed, the

are

copied

time

as

is

logic

when

cells

CIRCUIT ANALYSIS

-

TRANSMITTER BOARD

70-342~~1442~~

Each data 'word', or byte,

bytes by inputs from ports R20-R23, bit latch IC952 with

The second set of ElPROM data address immediately follows on the same

R20-R23 and R30 microprocessor ports--but bit-latch IC952 strobed. Thus, the second ElPROM address inputs while the first latched applied to the A2-A7 inputs. The parameter data byte then appears on the 00-07 ElPROM 'outputs.

When

from TX to After the E/PROM address sequence, port used when the second address activate chip enable and output enable inputs of IC951. The ElPROM then applies the data contained in the addressed location to IC902 through

Shift register IC902 loads the ElPROM data output when input applies eight pulses from causes each loaded bit to appear on IC902 one

cessor port

a

at a time.

a

combination of logic potentials present

AO-A10.

The microprocessor applies this address in two sets

R30,

a

channel

its

is

pulsed by microprocessor port

is

changed or the transceiver operating mode changes

RX

or vice versa, parameter data

00-07 outputs.

The eight bit string

Dl,

completing the ElPROM data read sequence.

is

addressed from the ElPROM bank of 2048

at

its

and

R31.

pulse from the R32 port that strobes IC952.

set

its

The first

is

applied to the

R31

is

applied) applies a logic high to

DO.

D2 port to IC902 clock input which

is

applied back to the micropro-

set

is

latched into six-

AO,

set

is

read from the EIPROM.

of the microprocessor (not

The microprocessor then

serial

data output pin

Al,

is

simultaneously

and

its

address

is

not

A8-A10

strobe

3,

TOP PANEL CONTROLS Various status inputs connect from, and control outputs connect to,

the front panel controls and option via microprocessor ports ROO-R03,

R10-R13,

dictates appropriate functions.

To display

logic potentials from

drivers IC301 and IC302 (in the control panel). The drivers decode

the latched-in logic high and low potentials, then gate current to

appropriate LED segments.

PHASE-LOCK-LOOP PROGRAMMING

Frequency dividers in the synthesizer phase-lock-loop

when the appropriate data word

processor. These dividers, that are within IC701, require bits (one bit time) to

IC701

Each bit

sort. After microprocessor port dividers.

D4-D7, and D10-D13.

a

channel number, the mi,croprocessor applies appropriate

its

is

the logic voltage present during a given instant in

set

A

and N counter values. Each bit

as

it

is

applied to the microprocessor from IC902 output port.

is

loaded concurrently with bit-clock pulses from IC901 D2

all

bits are loaded into IC701,

D3

A

respective logic potential on each

four DSPL outputs that

is

read from the

latches the loaded bits and reprograms the

are

latched into LED

are

E/PROM

is

loaded serially into

a

strobe pulse from the

programmed

by the micro-

a

string of

----------

NO.

----

10

11

12

13

1

2

3

4

5

6

7

8

9

NAME

------

D3

D4

D5

D6 D7

D8

D9

Dl0

Dl1

Dl2

Dl3

Dl4 Dl5 nc

RESET

GND

OSC osc2

HLT

TEST

vcc

ROO

R01 R02 R03 R10

R11

R12

R13

INTO INTl

R20 R21 R22 R23 R30 R31 R32

R33 DO

D D2

- - - - -

1

-

INPUT/ OUTPUT

OUT OUT OUT OUT

OUT OUT OUT OUT OUT OUT OUT OUT OUT

OUT

-

- - - - - -

.

OUT OUT OUT

IN

BOTH BOTH OUT

IN

OUT OUT

IN

OUT

IN

IN IN IN

IN

SIGNAL

NAME

C

- - -

DSTB+ TXTM-

ALM-

SQSIG+

TSQMON-

PLCL-

VCOCNTL

SCAN-

PRIDSPSTLDSPSTH-

ALBH-

TXDL

DSPO+ DSPl+ DSP2+ DSP3+

UP-

DWN-

INH+

TA-

PTT+

RMAO+ RMAl+ RMA2+ RMA3+ RMA4+ RMA5+ ASTB+

AUXSTB+

PSST+ CHDT+

DCLK

-

- -- - - - - -

MICROPROCESSOR (IC901) PINOUTS

--

- -

-

-.-------------------------------------------------------

Strobe for serial data to synthesizer TX/RX mode control to option (TX Mode Alert tone (2 KHz) Noise squelch status (HI LO in

=

Sq Tone decoded or MONITOR push button Scan activity (scan stopped = LO out) Synthesizer PLL status (LO in

RX

Mute and TX inhib during channel change,etc.=LO out VCO band switch control (Upper channels selected SCAN push button status (LO PRI push button status (LO Strobe for ONE'S digit of CHANNEL display data Strobe for TEN'S digit of CHANNEL display data A-band/B-band jumper status TX/RX Mode control (TX

CPU

Reset

(HI = Reset)

Clock oscillator (800 KHz +/-5%) Clock oscillator (800 Standby Mode (HI

=

Sleep)

not used

Vcc

(5 Volts, +/-lo%) LED Display data (8 Volt logic levels) LED Display data

(8

LED Display data (8 Volt logic levels) LED Display data (8 Volt logic levels)

CHANNEL UP pushbutton status (LO CHANNEL

DOWN

pushbutton status (LO = pressed)

PTT inhibit status (HI

Talk-Around select(HI=TX/RX f req

PTT (Push-To-Talk) status (HI not used E/PROM addressing

E/PROM addressing

E/PROM addressing E/PROM addressing E/PROM low-order addressing; or E/PROM Enable Strobe for E/PROM address latch Strobe for AUXILIARY data to option Strobe for E/PROM data out. into shift register IC902 Serial data from shift regi.ster IC902 Clock for CHDT+

FUNCTION

=

LO)

KHz

carrier

=

push button

+/-5%)

present)

=

PLL unlocked)

pushbutton

Volt logic levels)

=

pressed)

=

Deactivate PTT)

same;

=

PTT activated)

=

LO)

is

in

=

LO)

is

in)

is

in)

LO=TX/RX off set)

HI

=

3.5 to 5 Volts DC;

=

0 to 1.5 Volts DC

LO

CIRCUIT ANALYSIS

AUXILIARY DATA

as

Options such table. the option when the microprocessor initiates an E/PROM read-cycle. An E/PROM read sequence that loads the option read cycles by the presence of an auxiliary data strobe applied from the microprocessor port and latch the auxiliary data logic potentials simultaneously present on the ElPROM outputs.

PUSH-TO-TALK

The PTT logic low that applied to the interrupt input (INTO) of the microprocessor. This

forces the microprocessor to revert to

which

selected channel. After reading,TX channel frequency, port to the receiver (thus preventing erroneous activity while the synthesizer

is

reprogrammed). option, changes the display, and finally logic low and PLCL back to logic high. When PTT process repeats; except

and TXTM

Data

it

first reads E/PROM data

a

are

CTCSS are programmed from data in the ElPROM parameter

is

transferred directly from the E/PROM data outputs to

logic low which inhibits the transmitter stages and mutes

switched back to logic high.

-

TRANSMITTER BOARD

is

distinguished from other

R33.

is

applied to IC706 where

It

then sends new data to the synthesizer and

RX

This strobe causes the option to load

it

is

inverted, then

its

radio transmit routine by

at

an address respective of the

sets

channel frequency data

TXDL and TXTM ports to

is

70-342~~1442~~

it

sets

released, the read and TXDL

PLCL

is

When the microprocessor

the port serves

(logic low) from the synthesizer phase lock loop. The out-of-lock

logic low from IC701 pin 10 also disables the transmitter stages and

mutes the receiver.

SCAN OPERATION

Most operating functions of the optional scan feature

within the microprocessor. Also, able to the microprocessor for BCLO operation. Therefore, only opera-

tor control circuitry SCAN and PRI front panel push buttons that apply logic low status to respective microprocessor ports.

ERROR CODES

Numerals '901,

display accompanied by continuous triple-beeps indicate the E/PROM module (IC951 and IC952) When the microprocessor

table from the ElPROM upon power-up,

until E/PROM integrity

as

an input to receive an out-of-lock indication

is

91'

not applying a logic low to

carrier

dedicated to scan. This

'92', '93' or '94' appearing in the channel

is

unplugged, unprogrammed, or defective.

is

unable to read the operating parameter data

it

is

returned or power

detection

continues this error routine

is

removed.

its

PLCL port,

are

is

already avail-

is

provided by the

performed

Numeral

triple-beep on power-up or channel change

remaining logic low, thereby indicating the synthesizer phase-lock-

loop cannot attain lock. The triple-beep sounds again when the radio

is

keyed

'95'

if

appearing in the channel display accompanied by one

the PLCL port

still

is

a result of the PLCL port

stays logic low.

CIRCUIT ANALYSIS -TRANSMITTER BOARD

SYNTHESIZER CIRCUITRY

The SYN-TECH mobile transceivers utilize two individual phase-lock-

loops (PLL). One always runs to produce, in receive mode, receiver injection frequency that standard) channel frequency. In transmit mode frequency for generation of

other PLL. The other PLL

produces actual channel frequency that Audio. Logic voltage control signals from the microprocessor frequency dividers, switch appropriate loop circuits, and activate the transmit string.

is

21.4 MHz below (low-side injection

it

produces a beat

a

20.48 MHz mix-down signal used in the

is

active only in the transmit mode and

is

phase modulated by Transmit

70-342~~1442~~

set

is

PLL

MAIN

RF

the main PLL (the one that Q708, and D702.

MHz in receive mode or channel frequency minus 20.48 MHz in transmit mode,

buffered signal second PLL. The other part of IC704 buffers that signal for frequency

division by prescaler IC703. Prescaler IC703 divides the VCO sample by 64 and 65 to produce approx-

imately 2.5 MHz divided by the programmable divider within IC701, leaving 2.5 KHz one of the two phase/frequency comparator inputs (also within IC701). The other comparator input of the 5.12 MHz output fixed ratio of 1024 within IC701.

Phase/frequency comparator output level with respect to frequency difference between noise and 4706. Clean DC potential in the VCO, which regulates VCO resonance.

PHASE-LOCK-LOOP

signal

is

produced by the Voltage Controlled Oscillator (VCO) in

is

buffered by Q702 for connection to the receiver mixer. This

master

at

Q703-collector

is

filtered by the main loop filter consisting of Q704, Q705,

is

always active).

Its

output, which

is

buffered again by part of IC704 and applied to the

at

its

output pin 5. The prescaled count

is

a

oscillator X701 output. The master oscillator

is

divided by two in IC702 and divided by

is

at

channel frequency minus 21.4

2.5 KHz reference produced by division

is

noisy DC potential that varies in

then applied to varactor diode D702

It

consists of Q707,

is

its

inputs. The

then

at

a

The signal loop described hereinbefore keeps the VCO output at whatever frequency mable dividers) signal that exactly matches the 2.5 KHz reference. When the VCO output drifts up in frequency, the 2.5 KHz loop feedback input to the phase/frequency comparator deviates slightly from the reference frequency; thereby causing the VCO steering voltage to shift. The DC shift brings VCO resonance back to the frequency deter-

mined by programmable divider division. To set channel frequency, the

programmable divider

will

result in correct VCO output frequency.

is

necessary to produce a divided-down (by the program-

is

programmed with a pre-calculated value that

CIRCUIT ANALYSIS

TRANSMIT PHASE-LOCK-LOOP

In transmit mode, transmitter channel frequency transmit VCO consisting of Q108 and Q109. VCO output

IC104 for application to the transmit RF preamplifier Q110. After only one stage of buffering in IC104, VCO output signal applied to Q112 mixer driver. The buffered transmit VCO output sample

is

mixed with the main PLL sample (channel frequency minus 20.48 MHz) by the double balanced mixer consisting of L119 and L120. The mixer output signal of 20.48 MHz

by sixteen to produce 1.28 MHz for application to phaselfrequency

comparator IC103.

A

reference frequency of 1.28 MHz, derived from master oscillator division by four in IC702, phase/frequency comparator through modulator Dl01 and D102. Comparator output

applied across varactor diode Dl04 to steer VCO resonance. If the VCO

drifts from exactly main VCO output plus 20.48 MHz, the steering potential corrects

main VCO output frequency. Thus,

the main PLL changes, the transmit PLL VCO output follows at 20.48 MHz

above; resulting in actual selected channel frequency.

is

DC potential that

its

-

TRANSMITTER BOARD

is

produced by the

is

amplified by IC108 and frequency divided

is

applied to the other input of the

is

filtered and buffered by Q106, then

resonance. This holds true regardless of the

as

channel frequency programming of

70-342~~1442~~

buffered by

is

also

LOCK DETECT

There

circuit the loop phase,

at

the microprocessor Dl5 and IC706 pin lock condition.

The transmit PLL lock detect circuit consists of IC102 gates that

subtract the signals to the two inputs of comparator IC103. When these inputs differ in phase, positive pulses appear

and their widths widen

lock condition the pulses are wide enough to turn removes bias to the transmit tion in the main PLL also results in

WIDEBAND TUNING

For the 70-342XL and 70-442XL transceivers to operate across the 24 MHz frequency spread, electronic tuning VCO, the receive preselector, the receive injection amplifier, and the transmit RF preamplifier. Tuning of the preamplifier, preselector, and injection amplifier using VCO steering voltage to vary bias to varactor diodes in the

tuned circuits.

is

a

lock detect circuit in each PLL. The main lock detect

is

internal to IC701 and produces a constant logic high when

is

in lock. When the two comparator inputs

as

is

while changing frequencies, negative going pulses appear

the lock detect output. These pulses cause a drop in voltage to

13

inputs to indicate the out of

as

phase difference increases. In an out-of-

RF

preamplifier. An out-of-lock condi-

Qlll

is

continuous across the frequency range by

turn-on through D107.

is

used in five areas: each

are

at

IC102 pin

Qlll

output of

13

on, which

,

-

CIRCUIT

ANALYSIS

-

TRANSMITTER BOARD

70-342~~1442~~

,

-.

Electronic tuning of each VCO

inductance into the VCO tank to shift

12 MHz. Certain frequencies must be programmed into the E/PROM (see Center Frequencies in the E/PROM Programming section) so that the microprocessor can determine if the selected channel

them. If above, the D9 port

In

the main VCO, the junction between L702 and L704

biasing of D708 which couples this junction to and C745. When a channel frequency

selected, microprocessor port D9 switches Q752 on which pulls DC potential at L704 low. Thus, D708

the RF ground to the coil junction, leaving L704 in the tank circuit. Electronic switching of the transmit VCO

Analog amplifiers in IC751 use a sample of the main VCO steering

voltage from Q706 to derive a tracking potential to bias varactor

diodes in tuned circuits. Because the PLL holds the main VCO steering

voltage

present

linear fashion, the steering voltage makes guide.

DC potentials channel frequency. Because varactor diode capacitance decreases with reverse bias increase, the net capacitance of the tuned circuits in

which the varactors are components of, decreases. Lower capacitance

results in an increase in tuned circuit resonance.

at

a

level relative to channel frequency (a higher voltage

at

high channel frequencies) and the voltage follows in a near

at

the two IC751 outputs increase with increase in

is

done by simply switching additional

its

operating

is

logic low; if below,

at

the lower end of the band

is

reverse biased which disconnects

is

identical to the main VCO.

limit

is

it

is

RE

ground through C744

a

good tracking voltage

window down

above or below

is

logic high.

grounded by on-

is

Because the main VCO resonance channel frequency spread by electronic tuning, also affected. D751 couples the microprocessor amplifiers in IC751 to compensate.

MODULATION

Transmit audio

1.28 MHz reference frequency feed path. Because the PLL

its

reference causes modulation of the transmit VCO output that drive the transmitter stages.

Transmit audio Odd order harmonics of the limited audio signal and L104. The contoured signal across phase modulator varactor diodes

VCO output to follow

is

integrated into the synthesizer in the transmit PLL

its

is

pre-emphasized, amplified, and limited in IC101.

is

also changed halfway through the

its

steering voltage

D9

port to analog

reference frequency, modulation of the

are

filtered by L103

is

buffered by Q103, then applied

Dl01

and D102.

will

is

used to

is

force

CIRCUIT ANALYSIS

The phase modulator consists of two LC tanks. Because the capacitance

is

in each tank varies with modulation voltage across the diodes. With the 1.28 MHz signal from IC702 applied to the first tank through C103, a phaseshifted copy of the Because the degree of phase shift

is

there variances in the tank resonance with modulation audio causes respective variances in the signal phase. This phase modulated 1.28 MHz signal tank to supplement the effect.

TRANSMIT

between the tank resonance frequency and signal frequency,

is

RF

Dl01

then applied to the following cascade connected varactor

PREAMPLIFIER

-

TRANSMITTER BOARD

or Dl02 internal capacitance, each tank resonance

same

signal voltage appears across the tank.

is

determined by how much difference

70-342~~1442~~

\

Modulated transmit carrier signal from the transmit PLL

fied by Q110.

wide frequency spread by varactor

ing voltage output. This produces approximately 50

5366 at any channel in the 24 MHz operating band. To prevent erroneous

transmission during PLL out of lock conditions,

QllO

to or the microprocessor.

when

QllO

its

collector tank

base

is

biased positive by PLL lock detect circuits

is

electronically tuned across the

QllO

that

is

biased by IC751 track-

Qlll

is

preampli-

mW

into 50 ohm

shuts down bias

CIRCUIT

ANALYSIS

-

RF POWER AMPLIFIER DECK

70-342https://manualmachine.com/442~~

The RF power amplifier

the radio. This three-stage amplifier produces up to 50

ohm 5392 from 20

is

sampled by a directional coupler to regulate gain of the first

stage for power control.

routing from the power amplifier to the antenna connector 5392 in

transmit mode or from 5392 to the receiver in receive mode.

TRANSMIT

RF signal from the preamplifier ohm cable to 5371. When CV501 na, reactance equals inductive reactance), leaving only the transformedto-50-ohm resistive element transfer.

The striplines from 4501 collector to Q502 base and attached capacitors transform impedance to match the transistor elements. ances appearing to transfer. Because the circuit necessary. Energy Q503 base in

all

RF

POWER AMPLIFIER STAGES

reactances appearing

a

similar

mW

is

part of the heat sink module on the

Watts

applied to

4501

is

collector

transformed and coupled from Q502 collector to fashion.

its

50

ohm input 5371.

A

diode gate network switches RF signal

is

applied to

is

peaked for maximum RF

at

5371

as

load across 5371 for maximum power

are

is

are

balanced allowing maximum power

not as critical, tuning

4501

balanced out (capacitive

Its

output level

base circuit via

at

rear

into

the anten-

All

react-

is

of

50

not

All

(D501), through the harmonic filter (L511-L514), to the antenna connector With tor If imbalance exists caused by a defect.

In transmit mode, the receiver input port 5372 and associated components have negligible'effect on RF signal signal to

As

develop between antenna and chassis. POWER CONTROL

A

input stripline by a PC runner adjacent to rectified by D502 to produce a DC voltage that varies in proportion to the square-root of forward power at the power. adjust potentiometer RV502. The differential amplifier consisting of 4505 and 4506 compares the detected voltage to R515, R516, and D504.

reactances from

are

all

at

correct impedance, thus maximum energy

a

peak cannot be obtained when adjusting the trimmer, an excessive

the only conductive route, R511 bleeds

sample of forward RF energy

balanced when CV504

reactances balanced, a resistive load appears to 4503 collec-

a

harmonic filter consisting of L511-L514 and C525-C5.29.

4503

collector circuit through the antenna switch

is

set

for maximum output

is

drawn by the load.

at

C521. C521 couples the

static

is

coupled from the harmonic filter

it.

a

1.3

volt reference established by

charges that may

The RF sample

at

5392.

is

CIRCUIT ANALYSIS RF POWER AMPLIFIER DECK

As

forward power increases, increased voltage

Q505 collector current which decreases forward bias current to Q504.

With 4504 bias reduced, the first RF stage Q501 source current

less. rate) thus decreasing forward power output until equilibrium with the power

set

ANTENNA SWITCH

Consequently, reduced current surges (at

into 4501 tuned collector circuit result in

point of RV501

is

-

achieved.

at

RV501

carrier

less

70-342https://manualmachine.com/442~~

tap increases

frequency

net energy,

is

,

RF signal to/from the antenna connector 5392

receiver port 5372 by diodes

are

diodes circuit. Reactances of L515, C522, C523, and C524 balance, allowing

the resistive

harmonic filter. When the diodes

low RF impedance. The altered reactance of the network coupling the receiver port presents

D501

Diode bias current flows from ground through

through

TX

couples the third transmit amplifier output to C521.

8

Volts.

unbiased; therefore they present higher impedance to the

50

ohm receiver load

D501

are

and RF blocking L510, through current limiting

forward biased during transmit mode, they present

a

D501

high RF impedance

and

at

D503.

5372 to appear

is

gated from C520 or to

In the receive mode both

at

the passive

at

L515. Forward biased

D503,

through L515,

R518,

to

CIRCUIT ANALYSIS

-

RECEIVER BOARD

70-342https://manualmachine.com/442~~

The receiver circuitry Board.

21.4 MHz and second IF frequency of 455 KHz. First local-oscillator injection signal plied from the synthesizer VCO. local oscillator signal to the low side

A

single integrated circuit, IC251, contains the second mixer, second local oscillator, second IF amplifier, demodulator, and squelch hysteresis circuitry. Audio amplifier IC252 provides up to 5

audio signal into Antenna signal from the diode gate antenna switch on the RF Power

Amplifier Board Local oscillator injection signal from the synthesizer on the Transmitter pin 5357 and on kits.

PRESELECTOR Antenna signal

sisting of five tunable-coil tanks and Q201.

outside

image frequency. 4201 gain

loss through the tanks.

It

Board

its

is

of dual-conversion variety with first IF frequency of

is

a

3.2 ohm speaker.

is

connected to the Receiver Board through 5356. Multi-

5358

pass-window are rejected, including most of the first I.F.

provide connection for various optional feature add-

is

applied to the 50 ohm preselector stage input con-

is

contained on one PC board--the Receiver

at

the low side of channel frequency and

A

crystal oscillator injects second

as

standard.

connected to the Receiver Board through

All

is

sufficient to compensate for insertion

RF frequencies

is

watts

ap-

of

5355.

For tunability across the specified 24 MHz channel spread, each of the five preselector tanks ing voltage resonance. By the nature of the diodes, increased reverse bias decreases variance in proportion to channel frequency.

Preselector amplifier Q201

power through Q204. In transmit mode

4204 and Q205. MIXER

Injection frequency signal cuit of mixer FET Q202. Preselector output Because both input signal voltages, injection and carrier, are applied to opposite phase terminals of Q202, they

As

a

result, two new.signals amplitudes and Because the drain circuit the difference frequency signal

The high DC impedance gate of Q202 DC voltage drop across R214 raises source terminal to 2.5 Volts. The potential at the gate, with respect to the source-terminal, negative 2.5 Volts. Hence, negative bias to Q202.

is

applied to varactor diodes in each tank to change tank

its

internal capacitance, hence preselector tank resonance

at

sum and difference frequencies of the input signals.

are

electronically tuned. Contoured VCO steer-

is

sourced by switched 13.6 Volt primary

R8V

is

logic low, which cuts off

is

superimposed into the drain-source cir-

is

applied to Q202-gate.

are

subtracted analogously.

are

produced that

is

tuned for 21.4 MHz by L208 and C220, only

is

amplified.

is

DC shunted to ground by R213.

at

vector-difference

is

then

FIRST I.F.

a

Crystal filter FL251 passes frequencies within

tered

art

21.4 MHz. L208 and L251 match the filter input and output

15 KHz window cen-

to circuitry when properly tuned. High-gain Q251 amplifies second I.F.

is

signal that

coupled to the second mixer within second I.F. IC251.

Impedance mismatch from component failure or incorrectly tuned L208 or L251 affects the filter characteristics, resulting in a distorted KHz passband. When modulation distorted portion of the modulation window

is

present on received carrier, the

will

attenuate part of the

15

signal, causing receiver sensitivity degradation.

SECOND I.F. The second oscillator includes

AND

DEMODULATION

a

20.945 MHz crystal (X251) and active circuitry within IC251. The 20.945 MHz oscillator output and the 21.4 MHz By leaving only the sum and difference frequency signals

The 455 KHz sec-ond mixer output KHz filters, EL252 and FL253, that pass only the down-converted

rier

is

I.F.

its

signal are applied to a double-balanced mixer within IC251.

configuration, the mixer nulls both input signal components

at

its

output.

at

IC251 pin-3

is

applied to two 455

car-

frequency and modulation within a 15 KHz window. Filter output

applied to the second I.F. amplifier and

limiter

at

IC251 pin

5.

The 100 dB gain second I.F. amplifier boosts even receiver zero-signal noise into clipping.

IC251 internal

limiter

output

is

applied to an internal quadrature

detector demodulator consisting of an external 455 KHz tank (L252) and

a

double balanced mixer within IC251. Mixer output

at

pin 9

is

demod-

ulated audio.

INJECTION AMPLIFIER First injection of channel frequency minus 21.4 MHz, from the synthe-

is

sizer on the the Transmitter Board, is

tuned by L209. L210 couples the injection signal into the mixer

its

with

sample of this voltage produce

secondary as part of the mixer source-terminal circuit.

is

extracted by C228 and rectified by D217 to

a

metering voltage that indicates injection level

amplified by Q203. Q203 stage

A

at

CM202.

1

"

The injection amplifier stage channel frequency spread by varactor diodes that are reverse-biased by contoured VCO steering voltage.

is

electronically tuned across the

RECEIVER

,.

Detected audio signal from IC251 pin-9

AUDIO

is

band-stop filtered at 73 KHz by L253 and C276, then buffered by Q257. 4257 output routes through a jumper

Attenuated audio signal returns through 5358,

at

5358 to the control panel VOLUME control through 5354.

is

routed through audio

gate Q259, then applied to maximum volume trimmer RV252. IC252 ampli-

fies RV252 attenuated audio signal to drive one of three speaker

configurations: 5 power connector 5391; 5 watts through T301 to

watts

into a 3.2 external speaker connected to

a

3.2 speaker connected to the control head (70-442XL only); or to the front panel speaker and series connected 4.7 ohm resistor combination leaving

1

watt

applied to the speaker (70-342XL only).

is

Positive bias squelch switch output source terminal net positive bias to turn drain terminals terminal

is

a

sourced to the gate terminal of audio gate Q259 by

at

IC251 pin

is

resistor biased below that voltage, which leaves a

it

on. The impedance across Q259 source-to-

is

then low to pass audio. Conversely, when

logic low, Q259

13

when carrier

is

biased off which blocks audio

is

present. Q259

its

gate

coupling.

SQUELCH

Detector output audio signal potentiometer RV251. The attenuated audio signal

is

also coupled to the squelch range

is

applied to two 60

KHz parallel tanks L254/C261 and L255/C263 to couple only the 60 KHz

component of demodulated noise floor signal to the squelch amplifier

at IC251 pin 10.

input, so does this 60 KHz component. The amplifier output at pin

As

the noise floor increases due to less carrier

11

drives detector Q252. 60 KHz voltage spikes are then rectified by

D252 and D253 to produce

a

noise floor proportionate DC level at IC251

pin 12.

A

sample of the 60 KHz noise-floor-indicating signal

by D254 for metering

at

CM201. The metering voltage

subtract from positive bias from R262, producing

is

also rectified

is

negative to

a

net positive DC

metering voltage that increases (positively) with carrier input level.

A

hysteresis circuit with input

mute gate 4254 with

sis

circuit input increases to 0.7 volts, output at pin

its

output

at

IC251 pin 12 controls the audio

13.

As

voltage to the hystere-

13

switches to

a logic high voltage to unmute audio circuitry. When carrier level

decreases, pin

13

does not switch back until voltage to pin 12 increases to 0.8 volts. This 0.1 Volt switching hysteresis prevents squelch

If

jitter

carrier

under threshold conditions.

is

present to provide unmuting positive bias to audio mute

gate Q259, the gate can remain muted by application of a logic low to

its

gate from three sources. Referring to the Simplified Squelch Circuitry Schematic following, a logic low can be applied from; 1) 5353 pin

microprocessor

1

when the synthesizer PLL

is

reloading synthesiz,er dividers; 2) 5353 pin 5 (TXTM)

is

out of lock or while the

in transmit mode; or 3) activation of Q261.

CIRCUIT ANALYSIS

CTCSS SQUELCH

Q261 can pull the audio mute gate input low when

from CIRCUITRY if logic low stopped on a channel with busy scan status (this port also applies a

logic low status back to the microprocessor when

2)

the microphone

from the optional CTCSS decoder (inverted by Q260) when or code

The CTCSS module

5903. Transmit and receive CTCSS tone frequency data

the Module by the DO-D5 E/PROM outputs and strobed by a pulse appear-

ing at the

R8V

through R295, resulting in muted receive audio (see SQUELCH

-

SIMPLIFIED, following). The audio

carrier

A,logic low

squelch

is

received.

applied to TSQ MON from the microprocessor when scan

R33

is

applied when the MONITOR push button

is

not in

is

port of the microprocessor.

-

RECEIVER BOARD

it

is

again unmuted (only

is

open) when one of the following occurs: 1)

items

its

hang-up clip;

connected directly to the ElPROM Module through

3)

A

logic high

70-342~~1442~~

positive biased

2 and 3 occur);

is

in or when

is

applied

a

correct tone

is

programmed to

A

is

Receive audio signal from FM detector output buffer Q257

through the CTCSS option board before application to the VOLUME con-

is

trol. The signal

the the subaudible CTCSS tone. When the option

transceiver, the audio signal path must be completed with

plug ~onnected to 5358 that shorts pins

low-pass filtered in the option board to remove

is

not included in the

4

and 5 together.

is

a

routed

jumper

SIMPLIFIED SQUELCH CIRCUIT SCHEMATIC

70-342https://manualmachine.com/442~~

TRANSMITTER/SYNTHE

I-------

I

[----

TONWMONlTOR DETECT INPUT TONE DECODE /MONITOR: LOW SCAN HOLD STATUS OUTPUT NOISE SQUELCH HOLD: LOW

/

I

TRANSMIT INHIBIT INPUT

HIGH: 1NHlBIT

I

SQUELCH SIGNAL INPUT HIGH:BUSV

/

1

I

TRANSMIT STATUS OUTPUT

/

I

HIGH:RX

I

LOW: TX

.---

I

L

IC 901

--------

OV: NSO CLOSED

RECEIVER BOARD

-1

Mr

TONE

'

f

TONE

5303 FRONT PANEL

I

2-281

R1O

5V:

CTCSS

TONE

INHIBIT

.

I

There

are

two metering receptacles, CMlOl and CM202, in the 70-342XL and 70-442XL transceivers. The MIDLAND LMR Test Set model 70-El0 can be connected to these receptacles; or metering potentials present at receptacle pins can be measured with

a

high input impedance voltmeter

referenced to transceiver ground.

'

TRANSMITTER BOARD

The three pin metering receptacle (CM101) ter

Board near

Amplifier Deck.

its

center, approximately two inches from the RF Power

It

provides two metering DC voltages that

--

CMlOl

is

located on the Transmit-

are

rela-

tive indicators of key signal levels in the transmitter and synthesizer circuitry.

CMlOl PIN MHz signal rectified by D709. The resulting DC potential

1

through a 22K ohm resistor. Typical voltage

is

1

Volt.

1:

SYNTHESIZER REFERENCE OSCILLATOR OUTPUT LEVEL. The 5.12

at

4703 collector

is

sampled through a 5 pF capacitor and

is

applied to CMlOl pin

at

this metering point

CMlOl pin 2: TRANSMIT RF PREAMPLIFIER OUTPUT LEVEL. The DC voltage drop across transmit preamplifier measurable

at

this pin. This DC voltage varys in proportion to the

current absorbed by the preamplifier output tank, thereby

QllO

emitter

resistor R175

a

is

null

(minimum) indicates output resonance and maximum power transfer to the

RF Power Amplifier Deck. Typical DC voltage at CMlOl pin 2

is

0.7

Volts.

RECEIVER BOARD

-

CM202

,

-

is

The three pin metering receptacle (CM202)

located on the Receiver Board at the edge adjacent to the right side-rail, next to Audio IC252 and

its

heat sink. CM202 provides two metering DC voltages that are

relative indicators of key signal levels in the receiver circuitry.

CM202 pin

produced first injection signal, after tuned circuit filtering, sampled across L210 secondary where the signal first mixer circuit. The sample potential

1:

FIRST LOCAL OSCILLATOR INJECTION LEVEL. Synthesizer

is

applied into the

is

rectified and the resulting

is

applied to CM201 pin 1 through

a

1000 ohm resistor.

is

DC

Tuning of L209 and L210 affects this metering voltage that typically

is

0.6 Volts.

CM202 pin 2: RECEIVED SIGNAL LEVEL. DC potential at this metering

is

a

point 60 KHz squelch noise detector output

biased, rectified sample the squelch detector output. The

at

Q252-collector

is

rectified to apply negative voltage to CM202 pin 2 that increases with received channel signal level decrease. Positive bias metering pin. Thus, net voltage on the pin

is

also applied to the

is

a

DC voltage that increases in proportion to received signal level. Typical voltage swing quieting signal. The setting of SQUELCH RANGE RV251

is

-.25 Volts with no received signal, to 1 Volt with full

will

affect this

metering voltage.

BLOCK

DIAGRAM

70-342https://manualmachine.com/442~~

-

0105

XUIS8C

I

NOISE FIL

-

IC103

A:138-18ZMHz

0106

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MIC(G)

RECEIVER

PC

BOARD

70-342https://manualmachine.com/442~~

TOP VIEW BOTTOM VIEW

SOLDER SIDE SEEN THROUGH PC BOARD TOP

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CONTROLmCABLE

70-442~~

INTERFACE BOARD SCHEMATIC DIAGRAM

(TR~~~-MO~~~)

CONTROL-CABLE INTERFACE PC BOARD

(TRUNK-MOUNT]

PTT OUT

PTT IN

MIC OUT

J1

S P DSP

0

DSP 1 DSP

2

DSP

3

UP D N DSP STH DSP STL GND TX LED MIC(G) 530

1

5302 PTT S303 MIC HANG UP CALL LED AUX 2 AUX

1

SWCIN) SW(0UT) VOL(IN) VOL(0UT) VOL(GND1 sa BUSY LED SP SP SP(G) SP(G) GND SP(G)

COMPONENT-SIDE VlEW

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DC VOLTAGES - TRANSMITTER BOARD

70-342https://manualmachine.com/442~~

TRANSISTOKS

EMITTER

(SOURCE)

2.5

1.8

2.5

7.3

*

4.7

7.3

0.3

0.0

0.5

0.0

1.4

SYMBOL

QlOl

Q102 4103 Ql05 Q106 Q107 Q108 Q109

QllO

Qlll

Q112

Q402

Q403

Q404

Q405

VCO Buffer

1.

/

Active Capacitor

FUNCTION

Modulator Buffer Modulator Buffer Modulation Driver Active Capacitor Steering Buffer Active Capacitor TX VCO VCOBuffer RF Preamplifier Bias Switch Mixer Driver

MODE

TX TX TX TX TX TX TX TX TX TX TX

-------------------

TYPE

2SC460B 2SC535B 2SC458C 2SC458C 2SC460B 2SC1906

2SK192A BL

2SK241GR 2SC1906 2SC458C 2SC1906

2SC458C

2SC1213C

2SC458C

Q501 Q502

Q503

Q504 Q505 Q506

Q701 Q703 Q704 Q705 Q706 Q707

Q710

I

2SC1906 I BOTH 1 1.9 1 7.3 1 1.4 1 RF Amplifier

TX RX TX RX TX RX TX RX

0.0

13.6

0.6

V751

I

4.5 TX

VCO

Band Switch

BASE

(GATE)

3.2

2.5

3.2

7.9

'*

5.4

7.9

0.0

1.2

0.0

1.9

0.7

0.0

2.0

0.0

8.0

0.0

0.7

0.0

0.7

0.0

0.6

2SC1971 2SC2539 2SC2694 2SB834Y 2SC458C 2SC458C

RF Predriver RF Driver RF Final Current Regulator APC Differential Amp. APC Differential Amp.

'bC535B 2SC458C 2SK117BL 2SC458C 2SC458C

2SK192A BL

Q752

1

2SC458C

/

HI

CHNL I 0.1 1 4.5 1 0.0 I RX

VCO

Band Switch

COLL.

(DRAIN)

8.0

3.2

5.0

8.0

7.3

8.0

7.3

2.9

8.0

7.6

0.0

TX TX TX

--

TX TX TX

BOTH BOTH BOTH BOTH BOTH BOTH

ANALOG IC's

,

TX/RX Control

Regulator Switch

RX

8V Off-Clamp

IC901 Reset Gate

LO CHNL

SYMBOL TYPE

0.8

-0.1

0.0

12.9

1.3

2.9

0.7

"3.3

0.6

"

5.0

0.0

------

--------

IClOl t DH1048

33:-

9. 0

13.6

";?

9.0

12.9

8.0

0.7

4.5

-

2.8

7.3

*

5.0

7.3

7.4

- - -

- - - - -

- -

- - -

- - - - . -

-

-.

-

- - -

-

-,

- - - - -

-

.

- - - - - - . - - - - -

-

- - - - - - - - -

-

- - -

-

I DC TX 3.8 4.5 3.8 0.0 4.5 8.0

!

-

----

----------

BUFFER/AMP TX 0.0 0.0 0.0 7.5 7.5 0.0 0.0 0.0

-

-----------

BUFFER/AMP TX 0.0 0.0 7.5 0.0 7.5 0.0 7.5 1.6

-

----

-----------

SW. RGLTR TX 8.0 13.6 8.0 0.0

0.0

8.0

RX

8.0 13.6 8.0 0.0 1.7 8.0

0.0

FUNCTION

0.0

------- -----

-----

----- -----

-----

5V REGLTR

1:::;

-------

113.8

-----

loso

-----

1

-----

:::

1

-----

---

1

-----

---I:-:

-----

I---

-----

I---

-----

10V

RGLTR

13.8 10.0

---

PIN NO.

MODE

I

1

1 2 1

314 1 5 16 17 18

2.4

0.0

"

3.5

0.0

+*

4.4

0.3

0.0

ANALOG IC's

continued:

Reference ascillator Buffer Main Loop Filter Main Loop Filter VCO

Steering Driver

Main

VCO

SYMBOL TYPE

----------- -------

-----

------

----

-----

~~1048

t

IDC

1

TX

1

14.51---I---I-

I---I---

FUNCTION

BUFFER/AMP

SW. RGLTR

PIN NO.

MODE 1 9

110

111

112 / 13 114 115 116

5V REGLTR

I

BOTH

I

--- I ---

I

--- I ---

I

--- 1 ---

I

--- I ---

.

- -

- - - -

- - -------

-----

------

----

-----

2930L5.0t-~~;-~,~~,-1 BOTH

1

---

--- 1 --- 1 ---

1

---

1

---

/---

1

---

Fold

Out

-

+$

:

Varies

with selected channel frequency.

3$+$

:

Varies

with

RV502

adjustment and power output..

,MICROPROCESSOR (IC90

1

)

PINOUTS

70-342https://manualmachine.com/442~~

-

----

PIN NO.

HI

=

3.5

to 5 Volts DC;

LO

=

0 to 1.5 Volts DC

f

NAME

D

3

D4

D5

D6

D

7

D8

D9 Dl0

Dl

1

Dl2 Dl3

Dl

4 Dl5 nc

RESET

GND

OSCl OSC2

HLT

TEST

vcc

ROO

R01

R02

R03

R10

R11

R12 R13

INTO INTl

R20 R21 R22 R23 R30 R31 R32

R33 DO

Dl D2

MICROPROCESSOR

SIGNAL

NAME

DSTB+ TXTM-

ALM-

SQSIG+

TSQMON-

PLCL-

VCOCNTL

SCAN-

PRIDSPSTLDSPSTH-

ALBH-

TXDL

--

DSPO+ DSPl+ DSP2+ DSP3+

UP-

DWN-

INH+

TA-

PTT+

RMAO+

RMAl+

RMA2+ RMA3+ RMA4+ RMA5+ ASTB+

AUXSTB+

PSST+ CHDT+

DCLK

INPUT/ OUTPUT

OUT OUT OUT

IN

BOTH BOTH OUT

IN

OUT

OUT-

IN

OUT

--

IN

OUT

IN

IN IN

IN

OUT OUT OUT OUT OUT OUT OUT OUT OUT

IN

OUT

(IC901) PINOUTS

-

Duplicate Chart

FUNCTION

_-___-_-_--___-____-____.---__---_---------------------------------_------------

Strobe for

serial

data to synthesizer

TX/RX mode control to option (TX Mode

=

LO)

Alert

tone (2 KHz)

Noise squelch status (HI

=

carrier

present)

LO in

=

Sq Tone decoded or MONITOR push button

is

in

Scan activity (scan stopped

=

LO out)

Synthesizer PLL status (LO in

=

PLL unlocked)

RX

Mute and TX inhib during channel change,etc.=LO out

VCO band switch control (Upper channels selected

=

LO)

SCAN push button status (LO

=

pushbutton

is

in)

PRI push button status (LO

=

push button

is

in) Strobe for ONE'S digit of CHANNEL display data Strobe for TEN'S digit of CHANNEL display data A-band/B-band jumper status TX/RX Mode control (TX

=

LO)

CPU

Reset

(HI = Reset)

Clock oscillator

(800

KHz +/-5%)

Clock oscillator (800

KHz

+/-5%)

Standby Mode (HI

=

Sleep) not used Vcc (5 Volts, +/-lo%) LED Display data

(8

Volt logic levels) LED Display data (8 Volt logic levels) LED Display data

(8

Volt logic levels) LED Display data (8 Volt logic levels) CHANNEL UP pushbutton status (LO

=

pressed)

CHANNEL

DOWN

pushbutton status (LO = pressed)

PTT inhibit status (HI

=

Deactivate PTT) Talk-Around select(HI=TX/RX f req same;LO=TX/RX off set) PTT (Push-To-Talk) status (HI

=

PTT activated) not used E/PROM addressing E/PROM addressing E/PROM addressing E/PROM addressing E/PROM addressing E/PROM low-order addressing; or E/PROM Enable Strobe for E/PROM address latch Strobe for AUXILIARY data to option Strobe for E/PROM data out. into shift register IC902 Serial data from shift register IC902 Clock for CHDT+

_---_-_-_______-___-----b------------------------------------------------------

TRANSMITTER

PC

BOARD (TOP VIEW)

70-342https://manualmachine.com/442~~

LEGEND:

GRAY

0

COMPONENT-SIDE PATTERN

RED

0

SOLDER-SIDE PATTERN AS SEEN THROUGH PC BOARD TOP

BLACK

0

COMPONENT-SIDE COMPNENTS

LEGEND:

RED

0

SOLDER-SIDE PATTERN AS SEEN THROUGH PC BOARD TOP

BLACK

0

SOLDER-SIDE COMPONENTS AS SEEN THROUGH PC BOARD TOP

NOTE: SOLDER-SIDE COMPONENTS APPEAR REVERSED WHEN VIEWED FROM TOP SIDE OF BOARD.

Fold

Out

-

70-230 1 MICROPHONE DETAIL

70-342https://manualmachine.com/442~~

PART DESCRIPTION Front Panel

Name Plate Front Case Dynamic Element PTT Switch PTT Button PC Board with components Transistor, 2SA1015 Transistor, 2SC536 Elect. Capacitor, lOuF, 50V Ceramic Capacitor lOOOpF Cushion, PTT Button Resistor, 270ohm, 1/4W Resistor, 470ohm, 1/4W Resistor, 180Kohm, 1/4W Cord with contacts Cord without contacts

Mic Plug, 4-pin

Rear Case Case Gasket Screw,

Case

Screw, Hang-up Button Screw, Front Panel Mic Hang-up Button Hang-up Button Washer Rear Case Plate Ballast Weight

PART NUMBER 70-010072

70-020022 70-010073 70-038004 70-183004 70-1 18007 70-075014 70-080025 70-080026 70-135002 70-132005 70-157015 70-141010 70-141016 70-141037 70-034074 70-034075 70-159015 70-01301 7 70-157016 70-151076 70-151078 70-151077 70-1 18008 70-151079 70-020024 70-151369

70-2

195

HANG-UP BOX DETAIL

70-342https://manualmachine.com/442~~

-

ITEM

NO.

1

2 3 4 5

6

7

8

9

10

11

12

13

14 15 16

17 18 19

DESCRIPTION Top Cover

Bottom Cover Slide Switch Hanger Spring Hanger Spacer Insulating Washer Cord Grommet Cord with pins Hex Nut, M3 Hex Nut, M2 Bind-Head Screw 3x8 Tapping Screw 3x8

Washer 3.2

Washer 2.6 Bind-Head Screw 2x6 Terminal Bind-Head Screw 2.6 x

8

Hex Nut, M2.6

PART

NO.

70-010068 70-010069

70-183003 70-158022 70-158023 70-151062 70-151063 70-156006 70-151064 70-151065 70-151066 70-151067 70-151068 70-151069 70-151070 70-151071 70-151072 70-151073 70-161074

-

.-,.-

EXPLODED MECHANICAL VIEW

(TRUNK-MOUNT)

Fold

Out

-

Midland Syn-Tech 70-342XL, 442XL, Syn-Tech 70-442XL Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual