Telex RadioCom TR-200 User manual

-) TELEX
Service Manual
PROFESSIONAL
WIRELESS
INTERCOMSYSTEM
TR-200 SERIES
TELEX,

Table of Contents
Page
...........................................................................................
CHAPTER 1-GENERALINEORMATION 1-1
GENERALDESCRIPTION
................................................................................................................ 1-1
SPECIFICATIONSTR-200
................................................................................................................. 1-2
CONTROLS
AND CONNECTIONS .................................................................................................. 1-3
ExternalControls
............................................................................................................................. 1-3
InternalControls
.............................................................................................................................. 1-4
CHAPTER2
. IDENTIFICATIONOF CIRCUITBOARD VERSION ................................................. 2-1
GENERAL
........................................................................................................................................... 2-1
~ . ~-~~
CHAPTER 3 . TRANSMITAND RECEI~ CIRCUIT BOARDS ....................................................... 3-1
TR-200 INSTRUMENTDISASSEMBLY
.......................................................................................... 3-1
TRANSMITBOARD
.......................................................................................................................... 3-3
CIRCUITDESCRIPTION
............................................................................................................... 3-3
................................................................ ...................................
ALIGNMNENTPROCEDURE , 3-3
VOLTAGE TABLES
- TRANSMITBOARD ................................................................................. 3-4
RECEIVE BOARD
.............................................................................................................................. 3-5
CIRCUITDESCRIPTION
.............................................................................................................. 3-5
.........................................................................................................
ALIGNMENTPROCEDURE 3-5
.........................................................................................
OPTIONS - CIRCUITDESCRIPITION 3-5
VOLTAGE TABLES
- RECEIVEBOARD .................................................................................... 3-6
I '
\ !
...
ELECTRICALPARTS RECEIVEPCB ASSEMBLY (879977-*) ................................................
3-15
ELECTRICALPARTS TRANSMITPCB ASSEMBLY (879976-*)
................................................ 3-17

List of Illustrations
Figure
1-1
1-2
1-3
2-1
3-1
3-2
. 1
Page
HeadsetXLR ConnectorWiring .............................................................................. 1-3
External Controls,TR-200
.................................................................................. 1-3
InternalControls,TR-200
........................................................................................ 1-9
Version Flow Chart
.................................................................................................. 2-1
.......................................................................................
Exploded View of TR-200 3-2
P.C. Board Assembly - Receiver (879977-)ComponentLayout
(ComponentSide)
.............................................................................................. 3-9
P.C. BoardAssembly - Transmit (879976-)ComponentLayout
(ComponentSide)
................................................................................................ 3-9
Transmit P.C. BoardAssemblyComponentLayout(Foil SideView)
................... 3-10
Receive
P.C. Board Assembly ComponentLayout (Foil SideView) .................... 3-10
. .
Schemat~cDiagram TR-200Version 4 ..................................................................
3-11
SchematicDiagram TR-2M) Version 3
.................................................................. 3-12
SchematicDiagram TR-200 Version
2 .................................................................. 3-13
SchematicDiagram TR-200 Version 1
................................. 1 ............................ 3-14

CHAPTER 1
GENERALINFORMATION
GENERAL DESCRIPTION
TheTelexModelsTR-200 and TR-200PBelt-pack
Transceivers
are designed with one transmit and
one receive channel.
TheTR-200isaportableunitwhich communicates
in fullduplex with eitherthe BTR-200 base station
or a mirrorimage TR-200.
Push-to-Talkwith Lock-to-TaLk featureswitchfor
the TR-200 and Push-to-Transmit
with Lock-to-
Transmitfeaturefor the TR-200P.
The TR-200 Transceiveroperates in thecontinuous
transmitmode with the audio, to
talk, activatedby
a switch. As many as four TR-200 belt-pack
transceivers can operatein a fully duplex network
with one Telex Model BTR-200 or BTR-200 II
Base Station.
The TR-200P Transceiveroperates in the Push-to-
transmit mode (the transmit and talk function
are
activated together). Any number of TR-200P
transceivers can be used
in a half-duplex network
with one BTR-200 or BTR-200
11 Base Station.
Operate only onetransmitterata time. Attempting
to usetwo transmitterssimultaneouslyon the same
channel
will causeinterference.

SPECIFICATIONS TR-200
Overall
PowerRequirements ......................................................... 6 AA cells (Alkaline, NEDA, MN 1500)
Nickel Cadmium Optional
CurrentDrain
................................................................................................................ typc 65 mA
TemperatureRange ............................................................................. 4 to 130'~(-20'~to 55'~)
Dimensions
........................................................................................... 4.25" W x 4.125" H x 2.0" D
(108mm
x 105mmx 51mm)
Weight
........................................................................................................ 1302(369g)with batteries
TransmitAntenna
......................................................................................... 114-wavewire (attached)
ReceiveAntenna
.......................................................................................... 114-wavewire (attached)
Transmit
-
RF Frequency Range ..................................................................................................... 150-216MHz
RF Frequency Stability ............................................................................ C Controlled,0.005%
RF Power Output ........................................................................................................ 50mW Typical
~.
Modulation ......................................................... .......................................... FM, 5000 Hz deviation,
115micro-seconds Pre-emphasis
. .
ModulationLimter ............................................................................................. InternalCompressor
Modulation Frequency Range
........................................................................... 300 to 5000Hz =dB
MicrophoneAudioInput
........................................................................................... 30 to 3500ohms
...
MicrophoneInput Sensluvlty .............................................................. 2 mV Dynamic,4 mV Electret
. .
Radiated Harmonics and Spurious Emissions ....................................................................... -45 dBC,
Exceeds FCC Specifications
FCC
....................................................................................... Type Accepted Under Parts90and 74
%
Receive
RF Frequency Range ..................................................................................................... 150-216MHz
RF Frequency Stabiltiy .................................................................... stControlled, O.QOS%Type
DualConversion Superheterodyne,
FM
...
RF Sensihvity .............................................................................. Lessthan 0.5 pV for 12dB SINAB
IF Selectivity ..................................................................................... 3 dB at 30kHz (CeramicFilter)
. .
Image Rejection .......................................................................................................... 70 dB or better
. .
Squelch Quietmg ........................................................................................................................ 90dB
SquelchThreshold
...................................................................................................... 1.OpV (Internal)
cp-~~~~ ~ . ~ ~~~- ~~ ~~~~~~~ - -- ~~ ~
.................................................................................................................
I
Signal:io-No~seRaao 90dB
Audio Output
.................................................................................. 32 mW into 600 ohms(Headset)
Distortion
............................................................................................. Less than 1% at Rated Output
FCC
.......................................................................................................... Notification Under Part 15

I
I CONTROLS AND CONNECTIONS
External Controls(ReferTo Figure 1-2)
Push-To-Talknock-To-Talk Switch: For Model
TR-200, this switch enables the talk function. For
VolumeOFJ?/ON Control: Thisthumbwheelcon- Model
TR-200J?, this switch enables the transmit
trolserves
as both an off/onswitchand as avolume and audio function and otherwise operates as
control. describedfor
TR-200.
Low Battery and Overmodulation Indicator
LED:,
Low Battery Indicator:
This is part of the
batterycheckcircuit.Whenthepower switchis
placed in the
"ON" position the LED will flash
one time
if the battery is good. A poor bkttery
will cause the
LED to illuminatecontinuously
and
a bad orunusablebatterywillnotcauseany
illuminationat
all.
Talk LED Indicator: cabeled "talk") Will be
illuminatedwhenever the
talk function on the TR-
200
ortransmitfunctiononthe TR-2DOP isenabled.
Headset Jack: A four pin XLR connector for
1nput.Output. The headsetjack will accept six dif-
ferent Telex Model Headsets. Compatible with
otherintercomheadsetswithfourpin
XLR connec-
tors that arewired
as shown in Figure 1-1.
Overmodulation Indicator: Uses the same MICROPHONE
GROUND
LED as the low battery indicator. During the
talk mode,
if the microphone gain is too high,
AUDIO
the LED will illuminatewhen talking.
OUT
02 9
WCROPHONE
AUDIO D Figure 1-1 BALANCED
Headset XLR ConnectorWiring
LOW BATTERYIOVERMODULATION
i INDICATOR LED
rTALK LED INDICATOR
f
&& USH-TO-TALK OFFION
LOCK-TO-TALK SWITCH
l..
. "
d
/
n
HEADSET
BELTCLI -- ~~~.
RECEIVE ANTENNA
/ 1
CONTROL
Figure 1-2
External Controls, TR-200
1-3

DYNAMICIELECTRET MICROPHONE
GAIN CONTROL
BATTERY COMPARTMENT
Figure 1-3
Internal Controls, TR-200
Internal Controls (Refer To Figure 1-3)
D~amiclElectret Switch: This switch allows
selection of "D" when using a Dynamic
Belt Clip: Combination Belt CliplSattery Cover. Microphone or"
E" when using an Electret
AccesstoBatteryCompartment,Microphone
Gain
Microphone.
Control and DynamicIElectret Switch is ac-
complished by removal of belt clip via a quick
NOTE: All Telex headsets that are used with this
release 114
turn fastener. intercom are dynamic microphones. Unit is
- - - - -
-
shipped* the*" position.
lvlicrophone Gain Control: Screwdriver adjus-
tableby removingbeltclipand prying outthesmd
Battery Compartment: Holds 6 AA batteriesin a
rubberplug
to the right of the screwboss. removablebattery holder.

CHAPTER 2
IDENTIFICATION OF CIRCUITBOARD VERSION
GENERAL
Version 1 unitsmay be identifiedby theabsenceof
two 1.2
pH chokesinthe cableconnecting the P.C.
board assembly to the headsetconnector. Versions
2, 3, and 4 have two such chokes immediately
following the
P.C. board connector. Of the three
later versions, the one
in which C45 (transmit
board)
is 4.7 pF is version 2. On versions 3 and 4
thispartis 0.1 pE Onversion 4 only R45 (trpsmit
board) wilI be a wirejumper or zero ohm resistor.
This part is
47 K on all earlierversions.
TWO 1 -2pH VALUE VALUE
CHOKES YES OF 0.1pF
OF JUMPER
IN
.
c45
TRANMIT
R45
LINE
TRANSMIT
BOARD BOARD
h0 4.7pF
VERSION
2 VERSION4
Figure 2-1
Version Flow Ch-irt
2-112-2 Blank

CHAPTER 3
TRANSMIT AND RECEIVE CIRCUIT BOARDS
TR-200INSTRUMENT
4. Unplug the battery and audio cables from the
DISASSEMBLY P.C. board assembly.
5. Lift the P.C. board assembly clear of the rear
1. Remove battery door and removebatteries. case.
2. Remove 3 each #4 and 1each #2 socket head
6. Unsolder the transmit and receive antenna
screwsfrom the back of the unit wires and removethe connectorassembly.
i
3. Turn the TR-200 overandremovethefrontcase
7. Unsolder shield tabs (3 places on transmit
half. board and
3 places on receive board) and
NOTE: When refitting the case front the volume separatetransmitand receiveboards.
controlknobmustbepositioned
so thatthepinsand
8. Reassembly is the reverse of ihe above proce-
slots mate properly. dures.
I Mechanical Parts
Receive ( 879977-*)
Transmit (879976-*)
Item No.
1
Description
MembranePlate
Volume Knob
TransmitPCB Assembly
Stub, li4Turn
Retainer
Cap Screw,#4
- 40 x 3/8", slotted
Cap Screw,
#2 - 56 x 5/8", slotted
Case-L*bel
~---~ ~ ~
Retainer
Strain Relief
ReceivePCB Assembly
I 16 I Battery Clip
17
L.E.D.R~~
1 18 1 Choke, 1.2 uH
. .
19 Terminal
I EI
Audio Coax
Ground Shield
Part No.
450464- 1
51847003
58714000
650270
640063-2
64211005
802239
810102
810103
970010-1
810101
450462
470630
450521
96590002
470620
1506243
810225
96599000
96605000
40055-3
Item No.
22
23
24
25
26
27
28
-29-
30
3 1
32
33
34
35
36
37
38
39
40
41
42
Description
Sprocket
'Screw,
#2 - 56x 1 18' flat head
L. E. D., Green
IDS connector, 4 pin
IDSCableAssembly
WueHarness Assembly
FCC LBbel
BattevP-ackGushion
~~
BatteryClip Cushion
Insulator Shield
Foam Strip
Board spacer, biva
Board Spacer
Nylon Snap Rivet, Black
Case,Front Assembly
Case,Back Assembly
Telex Label
Keypad
Connector Plate
BeltclipAssembly
4
Pin XLR, Male

2 PLACES
(TYPICAL 2 PLACES
4 PIN
WIRING DIAGRAM
5 PIN Li:-1
-
IAGRAM TRANSMIT RECEIVE
I 1
Figure 3-1
ExplodedView of TR-200

TRANSMIT BOARD
CIRCUITDESCRIPTION
From the headsetconnectorthe microphonesignal
is first amplified by Q3 and Q4. This pair has a
gain of 12 dB. Depending upon which type of
microphoneisused, S1
is setby theusertodynamic
or electret. Theelectret position provides an lldB
dropin gain tocompensatefortheextraoutput.
R9
istheuseradjustedmicrophonegaincontrol. UlD,
Q1 and Q2 form
a peak limiting amplifier which
responds to negative peaks exceeding about,.84
volt in amplitude. When such peaks are en-
countered, Q2 conducts and charges C12, driving
Q1towardpinchoff. Thisreducesthegain momen-
tarily until the input signal is reduced. Visual in-
dication of peak limiting is provided by LED 102
which is driven by U103 when the voltage at pin 3
exceeds the 1.3 volt reference. U103 is also used
to sense the end of battery life and lights LED 102
continuouslywhen this occurs.
D1(version 2 and later) isolates the time constant
of the amplifierfrom that of the LED driver. The
latter is much shorter than the former, and causes
theLEDto extinguishimmediatelyupon removing
theinputsignal. "O_nversion 1
the^^^ willremain
!it for severalsconds.
U1Cisan amplifierwhosegain iscontrolledby the
levelof audio enteringtherectifier atpin 16.
As the
level here increases,the gain is decreased and this
results in
a 2: 1 compression characteristic. Pre-
emphasisisadded by UlB. R23,R24, and C16 set
this at 115pS. Q5 is used to
turn the microphone
anmdoffandisdrivenby theqsh-to-talk latch
circuit. When SlOl
is pressedin and held, Q106is
drivenon viaD103. ThislightsLED 101and gates
on themicrophoneaudio. ReleasingS101turnsoff
themicrophone. U104 doesnotchangestateunder
these conditionsbecause C151 is dischargedwhen
the clock ispulsed.
If, however, SlOl is depressed
twicein quicksuccession,C151willbe chargedfor
thesecond clock pulse andthiswillsetU104. Now
,
the microphone is latched on via Dl04 and will
remain on until SlOl is depressed once again,
resetting U104.
Q7 is a Colpitts oscillatorwith the collector tuned
to the third harmonic. L11, VVCl and VVC2 are
added in serieswith the crystal to allow frequency
modulation of the oscillator. The oscillator is
operated 10
KHz below theseriesresonant point of
the crystal. This improveslinearityat the expense
of somestability. Q8is atriplerandQ9
is astraight
through amplifier. The carrier frequency is thus
nine times the crystal. C43, C44 and L7 function
as alow pass filter and matching network.
ALIGNMENTPROCEDURE
Equipment Required:
Deviation Meter
RF Power Meter
Frequency Counter
Audio Generator
DC Power Supply
1. Solderoneend of a50ohm coaxial cablefrom
the transmit antenna pad to ground. Connect
the other end to the deviation meter, power
meter, and frequencycounter.
2. Connectthe audio generatorfrom pin 1(hot)to
pin 2 (ground) of the P.C. board connector. Set
the output to 10mV at 1
KHz.
3. Setthe power supplyfor9 volts and connectit
from pin 11
(+) to pin 10 (-) of the P.C. board
connector.
4. Turn
R9 to maximum clockwise.
5. Depress SlOl twice quickly to latch on the
microphone.
If aligningwith boards separated,
groundpin 8 of the P.C. board connector.
6. Adjust L2, L3,
L4, C39 and C42for maximum
Dower.
NOTE: If adjustmenu are severly out of align-
ment and no output can be obtained, it may be
necessary to first adjust L2 and L3 for maximum
DC voltage at the emitter of Q8. Then adjust
LA
for maximum DC voltage at the emitter of Q9.
Now adjustC39 and C42 for maximum power.

7. Adjust L11 for the correct frequency. This is
printed
on Y 1 and stampedinto the rear case.
8. Repeat steps 6 and 7 as necessary.
9. Adjust I228 for a deviation off 3. KHz.
VOLTAGETABLES - TRANSMITBOARD

RECEIVE BOARD
CIRCUITDESCRIPTION
Signalsfrom the receive antenna proceed through
3 tuned circuits, Q101, and 3 more tuned circuits
to mixer Q103. OscillatorQ102 is a Colpittswith
the collectortuned to the second harmonic.
Y 101
operateson the fifth overtonewith C112and L107
acting as mode suppressor. From the mixer the
signal continues through FLlOl to second mixer
2. Connectthe audio voltmeterand SINADmeter
from pin 3 or 4 of the P.C. board connectorto
ground. Turn the volume control (R159) to its
halfway point.
NOTE: K aligningwith boards
separated, make the audio hookup from pin 6
to ground.
3. Setthe power supply for 9 volts and connectit
from pin 11
(+) to pin 10 (-) of the P.C. board
connector.
U~OIA. This downconvertsthe 10.7 MHz to 455
KHz. After passing through FL102, the signal is 4. Setthegeneratordeviationto+3
KHz at 1 KHz.
limited and detected by UlOlB. UlOlB contains Set the output levelto 1mV.
a quadrature detector which is tuned by L109.
5. Set the generatorfrequency to the receive fre-
UlOlC functions as a 16
KHz bandpass filter for quency. This is printed on
Y 101and stamped
operating the squelch. With no signal a large into the rear case.
amountof noise is present at UlOl pin 11and this
.
6. AdjustL109 for maximum audio.
is rectified by D101, loweringthe voltageatpin 12
to lessthan .65 volt. Thisswitchespin 14to ground
7- Adjust T101, L108, L109, L105, L104, L103,
and mutestheaudio. When asignal
is received,the VC102 and VClOl in turn for best SINAD.
noise at UlOl pin 11drops and causes the voltage
8. setthe generator output to 1 u~.
atpin 12to rise above.65 volt,releasing the clamp
,
on the audio. R122adiuststhebiascurrentthrough 9. Adjust R122 until the audio is squelched off.
R121, R120, and ~i01and is used to set tie 10. Reduce the power supply voltage to
7 volts.
squelch point. De-emphasis is provided by R117,
R125, and C128. U1A is an amplifier whose gain 11. Adjust R135 until LED 102just comes on.
is controlled bq' the level of audio entering-the
rectifier at pin 4. As the level here increases, the
gain isincreased and thisresults in a
2: 1expansion
OPTIONS-CIRCUITDESCRIPTION
characteristic, which reverses the processing done
in the transmitter. R159 is the user volume control ~t
may be desirable in some instances to gate not
and U105 drivesthe headset. only the audio on and off with the push-to-talk
button but also the transmitter itself. This would
be the case
if several TR-200 units which were
ALIGNMENTPROCEDURE
E uipmentRequired:
b SignalGenerator
Audio Voltmeter
SINADMeter
DC Power Supply
1. Solderone end of a 50 ohm coaxialcablefrom
thereceiveantennapad to ground. Connectthe
otherend to the signal generator.
transmitting on the same frequency were being
used
togeth~;--F~r-ths~pti~n,--R44, a jumper, is
removed and
46 installed.
For the TR-200 units which do not communicate
with
a BTR-200 base station, but instead are used
with a mirror image TR-200, sidetone must be
added. Unlike the base station the TR-200 does
not retransmitthe received signal. For this option
C51 and R46 are installed.

VOLTAGE TABLES - RECEIVEBOARD
4101
NOTE: If this part is absent, then surface
mount
part has been installed on foil side.
Pad designations
are the same.

1
VOLTAGE TABLES - RECEIVE BOARD CONTINUED
3-7/34 Blank

figure 3-2
P.C. Board Assembly - Receiver(879977-)
ComponentLayout(ComponentSide)
Figure
3-3
P.C. BoardAssembly - Transmit (879976-)
ComponentLayout (Componentdde)

~~~
-- ~p~
~ - -
Figure 3-4
TransmitP.C. Board Assembly
u ComponentLayout (Foil SideView)
1
ComponentLayout (Foil SideView)
-- I

Figure 3-6
I
I
Schematic Diagram TR-200
Version
4

1__-_-_--__-_--_-_1
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RECEIVE BOARD
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FOR BELTPACKTO RUI
I
B&TP*CK UDDN
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~-~~~~ ~~~~
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! TRANSMIT BOARD i I
Figure 3-7
Schematic Diagram TR-200
Version 3

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Figure 3-8
" 1 SchematicDiagram TR-200
Version 2