Harris HTlFM User manual

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If You Didn't Get This From My Site, Then It Was Stolen From
TECHNICAL
MANUAL
m
HARRIS
HARRIS
CORPORATION
Broadcast
Group
P.O.
Box
4290
Quincy,
Illinois
62305-4290

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-
--
HARRIS
HT
lF
M
TRA
NS
MIT
TER
FI
I\
IAL
TEST
DAT
A
DATE:
28
Sep
1990
Til-1E:
06:
54:
50
l<SJD
-
MORGAN
HI
LL
CA
Fi-·
equ
1
2n
cy
(MHZ ) :
96.1
TF
'O
(W
ATT
·; ) :
AC
Po
wer
Se
t
For:
240
'vP,C
60
HEFnz
F.0
.
#:
F950
2
40001
Tr
ansmitter
S/N:
MFGt:
..
S388890001
MF
":::10
370
30
0002
Ex
cite
r
RF
Amp
S./N
:
750
MFG 1( >:3(;
55
c;=t)
(i
(j2
F'
Al
~
'.
F Amp :3 /
N:
2923
P(
-4
2
S./N
~
MFG10805590001
F'A2
~'.F
Amp S /
N:
2926
F:F I
mpe
cl-::•.
nc
1
2 :
5(
)
Cih
iTtS
AUDIO
I m
peda
.
rice
~
21<
./
l:>
()
l)
CJ
h
rns
Comments:
COAX
18
~8
INC
H
ES
RELEASED
F
OR
SHIPM
E
NT
Dat
e :
Date:
q/2-a/20
?,/7-
s
I
c;
c;
o/z
~~~

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-
-
PROOF
OF
PERFORMANCE
I.
EXCITER OPERATIONAL
FUNCTION
CHECKS:
1
. I
ND
I
C('1
TOF?S:
OK
::i •
r-:;:Et10TE
Crn-ffROU3:
cw:
,...,
I_OCAL
METEr-:;:ING:
rn:::
6.
'v'SWR
SHUT
DOW~~:
iJt:::
.,.;.;..
'
f?EMOTE
METEr-:;:
I
!"
-.
ii:;
~
OK
7
,
LOCl<
·-U
P'
TIME:
DI<
·-·.
.
4.
L.DCAL.
C;iJNTr-:;·OU3:
m:
: i3.
AGC:
[it:::
II.
EXCITER
MULTIMETER
READINGS:
3.
PA
CURRENTCPAil:
~-~
AMPS
T
T
T
1
.L
J.
..
2.
PA
VOLTAGECPAE):
15.0
VDC
5 .
FORWARD
POWER:
CONTROLLER
FUNCTION
CHECK
S:
;
.L
:1
2.
LOCAL
METERING:
OK
~-
REMOTE
METERING:
OK
4.
LOCAL
CONTROLS:
OK
4.
REFLECTED
POWER:
5.
REMOTE
CONTROLS:
OK
6.
VSWR
SHUTDOWN:
Di<
8.
EXT
nnr-:;·u:::
cw:
IV.
CONTROLLER
MULTIMETER
READINGS:
; I
'-.I
"
1.
PA
VOLTAGECPAE):
50.0
VDC
~-
PA
CURRENTCPAI
) :
27.8
AMPS
2.
Ft,,.JD
P!_;JF':
100.
0
i:
4.
'v'SV-J~'.:
1 . 0
5..
AFT:
6.
BAT
TEST:
POWER
AMPLIFIER
PARAMETERS
MEASURED
AT
TEST POINTS:
1•
F•Ol,,JEF:
1'.:fr
1P
L
IF
I
Er-:;
: 1 (
TDP)
:
a.
Voltage
test
point:
50
VDC
b.
Current
test
point:
1.55
VDC
=
X10
=15.5
AMPS
2.
POWER
AMPLIFIER 2 (BOTTOM):
a.
Voltage
test
point:
50
VDC
b.
Current
test
point:
1.26
VDC
=
X10
=12.6
AMPS

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•
-
VI.
PERFORMANCE
DATA~
1.
CARRIER
FREQUENCY:
96.
100000
l·IH:Z
2.
RF
POWER
OUTPUT:
753
t;JATT'.3
"'.;
·-·
..
POWER
AMPLIFIER
EFF
ICIENCY @
-re:--:-,-
/ ...J-~·
WATTS:
54
'i~
4.
RF
SAMPLE
OUTPUT:
-31
dBc
5.
COMPOSITE INPUT
LEVEL
TO
OBTAIN
75
KHZ
DE
VIATIO
N:
.
999
VRMS.
6.
BALANCED
COMPOSITE
TEST
DATA
f-=-~'EO
(HZ )
1
()(;{)
400
8•
:)00
J.
,6()()(;
32(;()()
64000
1.00000
IM
DISTiJRTIC:)N~
Fr-1
NOISE~
AM
ASYCHRONOUS
NOISE:
AM
SYCHRONOUS
NOISE:
\).
\_) \
_)
.01
..
t)
l
• 0 L
()II(
)()
•
Ol
(;
:1
()()
.
01
0.00
-
..
()4
-.08
.0123
.,
!.
--83.
80
dB
-7
.,:i.
2
(1
dB
-66.10
dB
7.
MONO
TEST
DATA
WITH
PRE-EMPHASIS SET FOR:
DI
ST
(:
1
::)
It
()353
..
()355
.-,
-,.
..-
r-
,
"'
!.
_)
·-~·
::J
tJ
a
():::5.-:":J.
..
i)::.:;5.~
~.
::
():::s/::.,
,.
()3 -47
• 03t~. 1
75U:3
AUDIO
INPUT
LEVEL
TO
OBTAIN
75
KHZ
DE
VIATION:
10.11
dBm
F
~:EQ
(HZ)
100
30
60
2(i()
·"'
.-
. .
·•,
·
'+l_i•
._i
8(;c)
20()(;
4000
8()(ji)
15000
IM
DISTDF::-TION:
FM
r,1
□
I
SE:
~:ESP (dB)
-.01
-.01
().
()(}
-.04
-
..
\)3
.01
•
(i
1.
.04
.03
.0
4
"/
,.
-85
.4
0
dB
8.
SPURIOUS HARMONICS
ABOVE
-
85
dBc:
NONE
DIST
Ci.)
.
()45t)
.0460
....
l'I
r-\
.-
•
• l..J'tdl_.1
.0460
.0460
.0460
.0480
.
0490
.
t)53(i
n
i)62(j
Pi:HJE•
.
.::,
OF
.
.:;.

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If You Didn't Get This From My Site, Then It Was Stolen From
TECHNICAL MANUAL
HT 2S0FM -994 9233 002
HT S00FM -994 9195 002
HT lFM -994 9231 002
;fl HARRIS
2'-J kcn.?r Pa."""-\-;s-- Boo '-t22-2vg
r2e5ul~-r- ~u,1'-"e.S-.s t± 217 2-2.--Z..-82.uo
T.M. No. 888-2312-002
© Copyright HARRIS CORPORATION
1990 All rights reserved
Printed: February 5, 1990

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REV.#
DATE
002
02'05\90
ECN#
MANUAL
REVISION
HISTORY
PAGE
HT250/S00/1FM
988-2312-001
Pages
Affected
PCNDP-37 Replaced
the
following
pages:
Title Page,
iv,
5-4,
& all of Section
VI.
Added
Manual
Revision
History
Page
(MRH-l/MRH-2)
888-2312-002
MRH-1/MRH-2

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!WARNING!
THE
CURRENTS
AND
VOLTAGES
IN
THIS
EQUIPMENT
ARE
DANGEROUS.
PER-
SONNEL
MUST
AT
ALL
TIMES
OBSERVE
SAFETY
WARNINGS,
INSTRUCTIONS
AND
REGULATIONS.
This manual
is
intended
as
a general guide for trained and qualified personnel who are aware of the dangers inherent
in
handling potentially hazardous electrical/electronic circuits. It
is
not intended to contain a complete statement of all
safety precautions which should be observed by personnel
in
using this or other electronic equipment.
The installation, operation, maintenance and service of this equipment involves risks both to personnel and equipment,
and must be performed only by qualified personnel exercising due care. HARRIS CORPORATION shall not be respon-
sible for injury ordamage resulting from improper procedures orfrom the use of improperly trained orinexperienced per-
sonnel performing such tasks_.
During installation and operation of this equipment, local building codes and fire protection standards must be observed.
The following National Fire Protection Association (NFPA) standards are recommended
as
references:
Automatic Fire Detectors, No. 72E
Installation, Maintenance, and Use of Portable Fire Extinguishers, No.
10
Halogenated Fire Extinguishing Agent Systems, No.
12A
IWARNINGI
ALWAYS
DISCONNECT
POWER
BEFORE
OPENING
COVERS,
DOORS,
ENCLOSURES,
GATES,
PANELS
OR
SHIELDS.
ALWAYS
USE
GROUND-
ING
STICKS
AND
SHORT
OUT
HIGH
VOLTAGE
POINTS
BEFORE
SERVICING.
NEVER
MAKE
INTERNAL
ADJUSTMENTS,
PERFORM
MAINTENANCE
OR
SERVICE
WHEN
ALONE
OR
WHEN
FATIGUED.
Do
not
remove,
short-circuit or tamper with interlock switches
on
access
covers,
doors, enclosures, gates, panels or
shields. Keep away from live circuits, know your equipment and don't take chances.
!WARNING!
IN
CASE
OF
EMERGENCY
ENSURE
THAT
POWER
HAS
BEEN
DISCONNECTED.
!W
A
RNING!
IF
OIL
FILLED
OR
ELECTROLYTI
C
CAPACITORS
ARE
UTILIZED
IN
YOUR
EQUIP-
MENT,AND IF A
LEAK
OR BULGEISAPPARENTON THECAPACITOR CASEWHEN
THE UNIT IS OPENED FOR SERVICE OR MAINTENANCE,
ALLOW
THE UNIT TO
COOL DOWN BEFORE ATTEMPTING TO REMOVE THE DEFECTIVE CAPACITOR.
DO
NOT
ATTEMPTTO SERVICE A DEFECTIVE CAPACITOR WHILE
IT
IS HOTDUE
TO
THE
POSSIBI
LIT
Y
OF
A
CASE
RUPTURE
AND
SUBSEQUENT
INJURY.
WARNING:
Disconnect
primary
power
prior
to
servicing

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TREATMENT
OF
ELECTRICAL
SHOCK
1.
IF
VICTIM
IS
NOT
RESPONSIVE
FOLLOW
THE
A-B-Cs
OF
BASIC
LIFE
SUPPORT.
PLACE
VICTIM
FLAT
ON
HIS
BACK
ON
A
HARD
SURFACE
@~~
@s~m~
IF
UNCONSCIOUS,
OPEN
AIRWAY
LIFT
UP
NECK
PUSH
FOREHEAD
BACK
CLEAR
OUT
MOUTH
IF
NECESSARY
OBSERVE
FOR
BREATHING
CHECK
CAROTID
PULSE
IF
PULSE
ABSENT,
BEGIN
ARTIFICIAL
CIRCULATION
©
CIRCULATION
DEPRESS
STERNUM
11/2
T02
INCHES
APPROX
.
RATE
OF
COMPRESSIONS
--80
PER
MINUTE
APPROX.RATE
OF
COMPRESSIONS
---60
PER
MINUTE
IF
NOT
BREATHING,
BEGIN
ARTIFICIAL
BREATHING
TILT
HEAD
PINCH
NOSTRILS
MAKE
AIRTIGHT
SEAL
4 QUl~K
FULL
BREATHS
'-
REMEMBER
MOUTH
TO
MOUTH
RESUSCITATION
f
ONE
RESCUER
l
15
COMPRESSIONS
2
QUICK
BREATHS
[
TWO
RESCUERS
5
COMPRESSIONS
l
1
BREATH
MUSTBE MMENCEDAS
SOON
AS
POSSIBLE
NOTE:
DO
NOT
INTERRUPT
RHYTHM
OF
COMPRESSIONS
WHEN
SECOND
PERSON
IS
GIVING
BREATH
CALL FOR MEDICAL ASSISTANCE AS SOON AS POSSIBLE
2.
IF
VICTIM
IS
RESPONSIVE.
A.
KEEP
THEM
WARM
B.
KEEP
THEM
AS
QUIET
AS
POSSIBLE
C.
LOOSEN
THEIR
CLOTHING
D.
A
RECLINING
POSITION
IS
RECOMMENDED
II
WARNING: Disconnect primary power prior
to
servicing

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FIRST-AID
Personnel engaged in the installation, operation, maintenance or servicing of this equipment are urged to become familiar
with first-aid theory and practices. The following information is not intended
to be complete first-aid procedures, it is a brief
and is only to be used as a reference. It
is the duty of all personnel using the equipment to be prepared to give adequate
Emergency First Aid and thereby prevent avoidable loss
of life.
Treatment of Electrical Bums
1. Extensive burned and broken skin
a. Cover area with clean sheet or cloth. (Cleanest available cloth article.)
b. Do not break blisters, remove tissue, remove adhered particles
of clothing, or apply any salve or ointment.
c. Treat victim for shock as required.
d. Arrange transportation to a hospital as quickly as possible.
e. If arms or legs are affected keep them elevated.
NOTE
If medical help will not be available within an hour and the victim is
conscious and not vomiting, give him a weak solution
of salt and soda:
1 level teaspoonful of salt and 1/2 level teaspoonful of baking soda to
each quart of water (neither hot or cold). Allow victim to sip slowly
about 4 ounces (a half of glass) over a period of 15 minutes. Discon-
tinue fluid if vomiting occurs. (Do not give alcohol.)
2. Less severe burns -(1st & 2nd degree)
a. Apply cool (not ice cold) compresses using the cleanest available cloth article.
b. Do not break blisters, remove tissue, remove adhered particles ofclothing, or apply salve or ointment.
c. Apply clean dry dressing if necessary.
d. Treat victim for shock as required.
e. Arrange transportation to a hospital as quickly as possible.
f. If arms or legs are affected keep them elevated.
REFERENCE:
ILLINOIS HEART ASSOCIATION
AMERICAN RED CROSS STANDARD FIRST AID AND PERSONAL SAFETY MANUAL (SECOND
EDITION) -
888-2312-001 iii
WARNING: Disconnect primary power prior to servicing.

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Table of Contents
SECTION I Output Directional Coupler
...................... 4-1
DESCRIPTION Controller .
.. ......... .. ...................... 4-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-1
Power Supply ............................... 4-1
Equipment Purpose ............................. 1-1 Operating Circuits ............................ 4-4
Physical Description .. ...... ....... .. ........... 1-1
Metering Circuits ... .. .............. .. ...... . 4-4
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . .
1-1
Overload and Alarm Circuits ................... 4-4
FM Exciter ................................. 1-1 Power Control Circuits ........................ 4-4
RF Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
User Interface RFI Filter and Transient Protection .. 4-6
Splitter (HT
lFM ONLY) . . . . . . . . . . . . . . . . . . . . . 1-1
AC Power Distribution ........................ 4-6
500 Watt Power Amplifier
..................... 1-1
250 Watt Power Amplifier . ... ....... .......... 1-1
Lowpass Filter . . . . . . . . . . . . •. . . . . . . . . . . . . . . . . . 1-1
Directional Coupler ........................... 1-1
Controller ................................... 1-1
Multimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Controller Functions ................ .. ........ 1-3
Indicators
.. . ................... . . . ... ....... 1-3
Remote Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Remote Control Commands . . . . . . . . . . . . . . . . 1-4
Remote Control Metering Samples
.......... 1-4
Remote Status Indicators . . . . . . . . . . . . . . . . . . . 1-4
Equipment Characteristics . . . . . . . . . . . . . . . . . . . . . . . 1-4
SECTIONV
MAINTENANCE
Introduction
.................... . .......... .... 5-1
Purpose
.......................... . ... ........ 5-1
Station Records .
...... ..... . ................... 5-1
Transmitter Logbook
................... .... .. 5-1
Maintenance Logbook
....... ..... .. .......... 5-1
Safety Precautions
............................ 5-1
Preventive Maintenance
......................... 5-1
Filter Cleaning
......... ........ ..... .... .... 5-1
Blower Maintenance .......................... 5-1
Maintenance
Of Components ................... 5-1
Semiconductors
.......................... 5-1
SECTION
II
Capacitors .............................. 5-2
INSTALLATION Fixed Resistors
.......................... 5-2
Introduction ................ . ............... . . . 2-1 Transformers
............................ 5-2
Unpacking .................................. 2-1 Meters
................................. 5-2
Retur::3 and Exchanges
... ................ .. . .. 2-1 Relays
................................. 5-2
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 Switches
.. . ...... ....................... 5-2
Cooling Air Requirements
.................. . .. 2-1
Corrective Maintenance .. ........ .. .......... .. . 5-2
Transmitter Placement
....................... . 2-1 Troubleshooting
.... ... ............. ......... 5-2
Component Installation
......... ... ............ 2-1 Technical Assistance
.... ..... ....... ..... ...... 5-2
Reassembly Instructions
.... .... ..... .. .... 2-1
Alignment Procedures .......................... 5-2
Initial Checkout
.............................. 2-2 Voltmeter and Ammeter Calibration
............. 5-3
Connections to Remote Controls ................ 2-2 500 Watt PA Chassis, 250 Watt PA Chassis .
.. 5-3
External Fail-Safe Interlock Connections ......... 2-2 Voltmeter Calibration
.................. 5-3
BBS Connections ............................ 2-2 Ammeter Calibration ................... 5-3
SECTION III
OPERATION
Introduction
.... . .. ..... .............. ..... .... 3-1
Controls and Indicators .......................... 3-1
Preoperational Checks .......................... 3-6
Transmitter Turn
On and Checkout . ............... 3-6
Power Raise & Lower
......................... 3-6
Transmitter Shutdown
........................... 3-6
PA Bypass Procedure
.. ............... . ......... 3-6
Single PA Bypass Procedure -(HT 1PM) ......... 3-6
PA Bypass Procedure -HT 500 and 250FM ..... 3-6
Overload Set Procedure ......................... 3-6
Controller Calibration Alarm and Fault Settings
.... 5-3
Manual Power Control Limit Setting ......... 5-3
Automatic Power Control (APC) Limit Setting 5-3
Forward Power Meter Calibration ........... 5-3
SWR Meter Calibration ..... .............. 5-3
SWR Foldback Trip Point Setting ........... 5-3
Reject Load -Balance Detector Fault Calibra-
tion
................................... 5-4
Setting Foldback Power Level .............. 5-4
Low Power Trip Set ...................... 5-4
Procedure for Removing an RF Power Transistor from
a PA Module
................................. 5-4
Procedure to Mount New Transistor to PA Module
... 5-4
SECTION IV
PRINCIPLES OF OPERATION
Introduction
... ..... .. ....................... .. 4-1
FM Exciter . ....... .. ......................... 4-1
500 Watt Power Amplifier (PA) .................. 4-1
SECTION VI
PARTS LIST
Introduction
... . .......................... ..... 6-1
Replaceable Parts Service ....................... 6-1
250 Watt Power Amplifier
(HT 250FM only) ....... 4-1 SECTION VII
Power Combiner (HT lFM ONLY) ................ 4-1 DIAGRAMS
Output Lowpass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
-1
iv 888-2312-002
WARNING: Disconnect primary power prior to servicing.

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1.1. Introduction
This Technical Manual provides informa-
tion necessary to install, operate, maintain,
and service the
HT 250FM, HT 500FM, or
HTlFMBROAOCASTTRANSMITI'ERS.
Sections in this Technical Manual contain
the following information:
SECTION
I, GENERAL DESCRIP-
TION, provides a description
of
equipment features, identifies major
components and lists operating pa-
rameters and specifications.
SECTION II, INSTALLATION, pro-
vides unpacking, inspection and in-
stallation information, preoperational
checks, and power-on checks to en-
sure correct operation.
SECTION III, OPERATION, identi-
fies controls and indicators and pro-
vides equipment and operational pro-
cedures.
SECTION
IV, PRINCIPLES OF OP-
ERATION, provides a functional de-
scription and detailed diagrams with
theory
of operation.
SECTION
V, MAINTENANCE, pro-
vides preventive and corrective main-
tenance information and trouble-
shooting with instructions for equip-
ment servicing.
SECTION VI, PARTS LIST, pro-
vides information for ordering re-
placement components and assem-
blies.
SECTION VII, DIAGRAMS, pro-
vides block, logic, schematic dia-
grams, and other drawings required
for operation and maintenance.
1.2. Equipment Purpose
The HT lFM FM BROADCAST
TRANSMITTER (refer to Figure 1-1) is a
1000-watt
FM Transmitter (HT 250FM is a
250-watt
FM Transmitter and HT 500FMis
a 500-watt
FM Transmitter) designed for
continuous broadcast operation in the 87.5
to 108
MHz Commercial FM Broadcast
Band.
1.3. Physical Description
The entire unit, including the FM Exciter,
IPA, PA, associated powersupplies, meter-
ing, andcontrol circuitryis containedinone
cabinet. All required metering is provided
by a meter located
on the front panel of the
transmitter controller plus two meters lo-
cated
on the from face of the FNi Exciter.
Circuitbreakers are accessibleonthe front
panel
of the individual transmitter sub-
assemblies.
SECTION I
DESCRIPTION
1.4. Functional Description
Refer to Figure 1-2 for ablock diagram of
the system.
1.4.1. FM Exciter
The FM Exciter produces a frequency
modulated output continuously variable
from 3 to 55 watts into a 50-ohm load for
any channel assignment within the 87.5 to
108 MHzCommercialFMBroadcast Band.
Servicing is simplified as the
FM Exciteris
modular in concept. The metering panel
contains a true peak-reading audio meter
with a times
10 expansionrange and a mul-
timeter which monitors important
rf and
control voltages.
Light emitting diode
(LED) status indicators monitor critical
functions onthe exciter. The exciter accepts
wideband composite stereo/mono inputs
and has separate inputs for up to two SCA
generators.
1.4.2. RF Circuits
The entire rf chain in the FM Transmitter
utilizes 50-ohm interfaces as follows:
a. 50 ohms Exciter to Splitter.
b. 50 ohms splitter to 500W
PA.
c. 50 ohms 500WPA to Combiner.
d. 50 ohms Combiner to Antenna Load.
The convenience
of 50-ohm interface al-
lows patching around any stage during an
emergency fault condition. For example,
should the final
PA stage fail, the FM Ex-
citer can be patched directly into the an-
tenna, resulting in good local coverage. All
that is required is the disconnection
of the
input linefrom the
PA and thereconnection
to the input of the Lowpass Filter.
1.4.3. Splitter (HT lFM ONLY)
Theoutput of theExciteris routed through
a two way power Splitter on the rear panel
of the Controller. This provides equal rf
drive for the two SOOW PAs.
1.4.4. 500 Watt Power Amplifier
The final amplifier stage is a conserva-
tively rated 500 Watt amplifier consisting
of eightpowerMOSFET transistors operat-
ing in two push-pullparallel pairs. The am-
plifier incorporates a controller which
protects itself from operational faults and
abuse. Sensors detect over temperature,
high VSWR, overdrive and over voltage
conditions and disable the module until the
condition is corrected. The internal power
supply provides a regulated 50 VDC at up
to25 A.
888-2312-001
1.4.5. 250 Watt Power Amplifier
The250 WattPowerAmplifieris identical
to the 500 Watt PA butuses
half the number
of transistors in the amplifier module. All
other circuitry is the same.
1.4 . 6. Lowpass Filter
The FM Transmitter incorporates a fixed
tuned multi-element lowpass filter to pre-
ventthe emission
of harmonic and spurious
energy. Thisfiltercovers
theentireFMband
and requires no field or factory tuning for
any operating frequency, 87.5 to 108 MHz.
1.4. 7. Directional Coupler
Adual elementDirectionalcouplerisused
for monitoring of forward and reverse
power and to provide inputs for the auto-
matic power control and VSWR foldback
circuitry.
1.4.8. Controller
The Controller provides the following
functions:
a. Transmitter On/Off.
b. Raise/LowerPower.
c. Automatic VSWR Foldback.
d. Automatic Power Control.
e. AC Restart.
f. Remote Control Interface.
g. Overload Detection, Protection, and
Display.
1.4.9. Multimeter
Metering of the essential operating pa-
rameters
of the FM Transmitter is accom-
plished with a multimeter located
on the
CONTROLLER front panel. A pushbutton
selector switch, mounted next to the Mul-
timeter selects the following:
a. PAE (PA Drain voltage) 0-60 volts
b. PA I (PA Drain current) 0-30 A, 0-60 A
for
HT lFM
c. FWDPWR(ForwardPower)0-125%of
TPOWatts
d. SWR to 2.2:1
e. APC voltage 0-125%
f. BAT TEST 0-30V
The PA Voltage reading is the
drain volt-
age on the final amplifier.
In the case of the
HT lFM, the average voltage of the two
amplifiers is displayed.
The
PA Current reading is the drain cur-
rent
of the final amplifier. In the case of the
HT lFM, the sum of the currents for both
amplifiers is displayed.
FORWARD Power is a true indication of
power being supplied to the antenna sys-
tem. The Output Power sample is taken
from the Directional Coupler which is the
1-1
WARNING: Disconnect primary power prior to servicing.

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0
0
0
0
0
0
0
1-2
I (8) HARRIS I I
HT lFM I
==================== TJJJ:-l lJJ llCf/1R =
I (8) HARR Is I
-----------CONTROLLER-
l~I
NULTJHETER
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r;-;-
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ltitMilC HA X X JOVJr:
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PIJllat rH.LT
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Io o o I <'ff)
....__ SLPPLY ----' LJ
rm
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Figure 1-1. HT lFM Front View
888-2312-001
WARNING: Disconnect primary power prior to servicing.
0
0
0
0
0
0
0

www.SteamPoweredRadio.Com
HT
250FM
HT
500FM
THE-1
EXCITER
APC
PA
LOW
PASS
FILTER
CONTROLLER
ANT
COMMAND
&
STATUS
2303-023
ANT
HT
1FM
ONLY
THE-1
EXCITER
SPLITTER
COMBINER
LOW
PASS
FILTER
APC
CONTROLLER
'-------------l
-----------
COMMAND
&
STATUS
connectionto the antenna and located at the
output
of
the lowpass filter.
SWR
is a ratio reading (example 1.15:1)
on
the POWER meter.
APC voltageis a relative indication
of
the
functioning
of
the automatic power control
and VSWR foldback loop. It is provided to
facilitate setup ofthe transmitter APC loop.
BAIT
TEST: Checks voltage
of
the op-
tional 9-Volt Controller battery which is
used for long term retention
of
the control
settings.
A
push-to-test pushbutton switch
eliminates the possibility
of
leaving the
MULTIMETER in this test position and
draining the battery.
NOTE
The control settings (TX ON-TX
OFF
state
and
power level setting) are backed
up
for at least five hours during power
outages by a capacitive storage device.
If
longer outages are anticipated, a bat-
tery may be installed.
N
OTE
The 9-Volt battery used
is
a common va-
riety
transistor
radio
battery
(DO
NOT
USE
ALKALINE
BATTERY)
.
In
normal
operation,
the
battery
has
no
drain
on
it
Figure 1-2. HT250/500/lFMBlock Diagrams
nor does it receive a charge. Depending
on the freshness
of
the battery at the
time
of
installation, typical life
is
ex-
pected to be a year plus. The battery,
if
called upon, should provide at least
30
days
of
control setting retention.
PA
voltage,
PA
current, forward power,
and VSWR readings are all available for
remote control monitoring. These readings
are all positive when referenced to ground.
1.4.10.
Controller Functions
The Controller Panel has the following
control functions:
TX
ON/TX
OFF-Selects transmitter ON
or OFF
LOCAL/REMOTE -Selects either local
orremote command
of
the transmitter. Ared
LED is illuminated with the switch in the
LOCAL Mode reminding the operator
to
switch to remote control before leaving the
remote site.
RAISE/LOWER -Raises and lowers the
transmitter output power.
1.4.11.
Indicators
POWER. Indicates
AC
power is applied
to
the
Controller
888-2312-001
chassis.
VSWR
FAULT.
Indicates the initiation
of
VSWR foldback
as
set by the threshold
control in the Controller. This fault will
automatically clearwhen the VSWRcondi-
tion is removed.
PA
FAULT.
Initiates a power tumdown as
set by the foldback setting in the controller.
The
PA
FAULT occurs when either one
of
the amplifier module protection levels has
beenexceeded, or when the a voltage regu-
lator heatsink has exceeded 85°C. The am-
plifier protection levels are 3:1
VSWR,
82°C heatsink temperature, collector volt-
age >54V, and drive >70W. The fault pro-
tection will automatically clear when the
fault condition is cleared.
BALANCE FAULT. Shuts
down
the
transmitter when the voltage across the re-
ject load in the combiner exceeds the Bal-
ance
threshold.
The
fault
latch
is
automatically cleared when the
TX
ON
command is given.
EXTINTRLK (External orFailsafe Inter-
lock). Provides an
interlock circuit with external pieces
of
equipment such
as
water-cooled dummy
1-3
WARNING:
Disconnect
primary
power
prior
to
servicing.

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loads, air-handling systems, combining
equipment, etc. When this external contact
is opened, the transmitter will shutdown or
willbepreventedfromcomingup andwhen
this occurs the EXT
INTRLK
LED will
illuminate. After the external interlock
closes, the transmitter will comebackup or
may
be
turned
on
and the
EXT
LED will be
extinguished. There is
no
memory to this
indicator. This external interlockcommand
interrupts the ac line contactor supply.
NOTE
The external failsafe interlock is a series
loop circuit. The external interlock must
provide a contact closure between termi-
nals 1 and 2 on terminal board TBJ on
the rear panel
of
the Controller chassis.
Automatic VSWR Foldback. The Con-
troller constantly monitors the reflected
power sample from the transmitter Direc-
tional Coupler. If the reflective sample ex-
ceeds
the
threshold
(adjustable),
the
Controller automatically lowers the EX-
CITER
drive which lowers forward output
power and the relative amount ofreflective
powerdetected
by
the Directional Coupler.
The Controller continues lowering output
power until the reflective voltage sample is
below thesafethresholdlevel. TheControl-
ler constantly monitors the reflective volt-
age level. Whenan antenna icing condition
beginsto clear, and the loadbegins toreturn
to normal, the Controller automatically in-
creases power to the safest level. The auto-
matic
VSWR
foldback circuit does not
lower the antenna system
SWR,
that ratio
remainsconstant. Thecircuitmerelylowers
forward
power
which
in
turn
simulta-
1-4
neously lowers reflective power to a safe
system operating level, thus keeping the
station on the air. This function is active
regardless
of
the selection
of
APC
ON
or
OFF.
AutomaticPowerControl. TheAutomatic
Power Control circuit is similar to the auto-
matic
VSWR
foldback circuit. After the
transmitter has been adjusted for desired
output power, the automatic power control
automatically maintains power to within
+/-5%. The Automatic Power Control may
beenabledordisabledby aswitch inthetop
cover
of
the
Controller.
For
example,
shouldafront panel
or
remoteraise
or
lower
command be given, the transmitter power
will raise
or
lower. The Automatic Power
Controlisonlyoverriddenbyinputfrom the
automatic
VSWR
foldback circuit which
will lower and maintain power at a safe
operating level under high-load VSWR
conditions.
AC Restart. AC Restart automatically re-
turns the transmitter to its previous state
(either ON,
or
OFF) after an AC Power
failure. Except for the lock-up time
of
the
AFC loop inthe Exciter, there is
no
warmup
delay at
TX
ON.
1.4.12.
Remote
Control
Allconnectionsaremadeonalarge, easily
accessible terminal strip located onthe rear
of
the Controller chassis. The following
controlfunctions, metersamples, andstatus
indicators are all available for remote con-
trol and indication. These commands all
require a momentary contact closure be-
888-2312-001
tween the desired command line and Com-
mon (Chassis):
1.4. 12.1.
Remote Control Commands
1.
TXON
2.
TX
OFF
3.
POWER
RAISE
4.
POWER
LOWER
5. EBS Keying
1.4.12.2.
Remote Control Metering Sam-
ples
1.
PA
Voltage
2.
PA
Current
3. Forward Power
4. Reflective Power
1.4.12.3.
Remote Status Indicators
1.
External Interlock Fault
2. Output Power Fault (Output power
less than threshold setting)
3. SWR FOLDBACK
4.
BALANCE FAULT
5. VSWR (ANTENNA)
When activated, these status outputs go
"low." Remote metering is typically a pos-
itivevoltage. All remoteindicators andcon-
trols are "open collector, common ground"
compatible.
1.5.
Equipment
Characteristics
Table
1-1
lists the electrical operating
characteristics and parameters for the
FM
Transmitter as well as the mechanical char-
acteristics.
NOTE
Specifications subject to change without
notice.
WARNING: Disconnect primary power
prior
to servicing.

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Table 1-1. Electrical and Mechanical Characteristics
GENERAL
POWER OUTPUT RANGE
HT250FM
55 to 265 watts
HT500FM
235 to 525 watts
HTlFM
300 to 1050 watts
FREQUENCY
RANGE
87.5 to 108 MHz in 50 kHz steps
EXCITATION Harris THE-1
High Power FM Exciter or equivalent
TYPE OF MODULATION Direct carrier frequency modulation (DCFM)
MODULATION CAPABILITY
+/-200kHz
LOAD IMPEDANCE
50ohms
OUTPUT TERMINATION N female (HT 1PM: 7/8"
EIA flange, female)
MAXIMUM LOAD VSWR i.5:1 VSWR, maximum for full output power;
automatic power reduction into high VSWR's.
RF HARMONIC/SPURIOUS OUTPUT
Suppression meets or exceeds FCC/DOC/CCIR specifications
AC INPUT POWER
197-250 Vac, 50 or 60 Hz, single phase, 2-wire
POWER CONSUMPTION
HT250FM
500 watts
HT500FM
1000 watts
HTlFM
2000 watts
AMBIENTTEMPERATURE RANGE 0 to +45°C at sea level; derated 2°C/lO00 ft altitude
MAXIMUM ALTITUDE 10,000 ft (50
or 60 Hz)
MAXIMUM HUMIDITY To
95% non-condensing
CABINET SIZE
22-l/8"W (56.2 cm) x 25-1/2"D (64.8 cm) x 72"W (182.9 cm)
WEIGHT
HT250FM
185 lbs
HT500FM 275lbs
HTlFM 400lbs
888-2312-001
1-5
WARNING: Disconnect primary power prior to servicing.

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2.1.
Introduction
This section contains information for the
installation
of
the low powerHT line
of
FM
BROADCAST
TRANSMITIERS
and for
performingthepreoperationalchecks. Gen-
erally, the individualchassis assemblies are
individually packed for shipment and must
be
installed in the appropriate rack shelf.
These components will
be
identified with
appropriate instructions for reinstallation
and wiring.
2.1
.1.
Unpacking
Carefully unpack the
FM
Transmitter and
perform a visual inspection to determine
that
no
apparent damage was incurred dur-
ing shipment. Retainthe shipping materials
until it has been determined that the unit is
not damaged. Thecontents
of
the shipment
should
be
as
indicated
on
the packing list.
If
the contents are incomplete or
if
the unit
is damaged electrically or mechanically,
notifythe carrierandHARRIS CORPORA-
TION, Broadcast Division.
2.1.2. Returns and Exchanges
Damaged
or
undamaged
equipment
should not
be
returned unless written ap-
proval and a Return Authorization is re-
ceived from HARRIS CORPORATION,
Broadcast Division. Special shipping in-
structions and coding will
be
provided to
assure proper handling. Complete details
regarding circumstances andreasons for re-
turn are to
be
included in the request for
return. Custom equipment or special order
equipment is not returnable.
In
those in-
stances where return
or
exchange
of
equip-
ment is at the request
of
the customer,
or
convenience
of
the customer, a restocking
fee will
be
charged. All returns will
be
sent
freight prepaid and properly insured by the
customer.
When
communicating
with
HARRIS CORPORATION, Broadcast Di-
vision, specify the HARRIS OrderNumber
or
Invoice Number.
2.2.
Installation
Prior to installation, this Technical Man-
ual and the
FM
Exciter Technical Manual
should
be
carefully studiedto obtain a thor-
ough understanding
of
theprinciples
of
op-
eration, circuitry and nomenclature. This
will
facilitate proper installation and initial
checkout. The
FM
Transniitter installation
is accomplished infour steps: (1) transmit-
ter placement, (2) component installation,
(3)
transmitter wiring, and
(4)
initial check-
out.
SECTION
II
INSTALLATION
2.2.1. Cooling Air Requirements
Harris transmitters are alwaysdesigned to
operateina free, unobstructed environment
with a maximum inlet
air
temperature
of
50°C. This means that the transmitter air
system is designed to supply sufficient air
at the required static pressure to cool the
transmitter only. Any additional pressure
loses introduced by air exhaust systems &
air supply systems must
be
satisfied by
means other than the transmitter blowers.
These inlet & exhaust systems generally
need to
be
fan driven.
2.2.2. Transmitter Placement
Set the transmitter in place
on
a level
surfacenearpowerandsignal cables. Either
side
of
the
FM
Transmitter may be placed
against a wall or other equipment. Com-
plete access is through the front and rear
of
the transmitter.
The floor must be capable
of
supporting a
load
of
120poundsper-square-foot(58.6kg
per-square-meter) (refer to applicable cabi-
net outline drawing listed in Section 7).
2.2.3. Component Installation
The removal
of
components varies due to
the method
of
shipment. All removeditems
will
be
tagged to aid reinstallation in the
transmitter. Arrange these components in
separate groups according to the section
from which they were removed. Items such
as interconnecting wires and cables and
miscellaneous small parts may
be
taped
or
tied
in
for shipment. Remove all tape,
string, and packing material that has been
usedfor this purpose. Symbol numbers and
descriptions are provided
on
each removed
component corresponding to the schematic
diagram,parts list, andpacking list. Symbol
numbers are also stenciled in the cabinet
of
eachremoveditem.Terminals andwires are
tagged with in formation telling how to
reconnect each item. Mounting hardware
should
be
found either in small bags at-
tached to each remov
ed
component or in-
serted
in
the
tapped
holes where
each
component mounts. Reinstall each compo-
nent in its proper location.
2.2.3.1. Reassembly Instructions
Depending
on
the particular model and
the method
of
shipment,itmaybenecessary
to reassemble the Transmitter. Each
of
the
separate chassis assemblies fits onto a shelf
which is then fitted into a cabinet rack.
On
some models, the Transmitter can
be
pur-
chased for installationinto an existing rack.
888-2312-001
In
any case, it is important to stack the
individual componentchassis in the proper
order to obtain optimumperformance.
The
exciter,
THE-1,
is on top and theController
next. ThePowerAmplifiersarelowest.This
configuration assures minimuminteraction
between units, and maintains a low center
of
gravity.
If
the Transmitter has been shipped
in
the
rack, it will be necessary to remove the
shipping hardware
on
the Power Ampli-
fier(s). To prevent movement during ship-
ping, two screws are usedto secure therear
end
of
the chassis to the mounting shelf.
These must
be
removed. starting with the
lower chassis. There are
no
rear screws
on
the Controller or Exciter.
The ac input for the transmitter should
come from low impedance, 50/60 Hz, sin-
glephase supply with sufficient capacity to
supply the transmitter. A terminal board is
locatedinside the AC distributionassembly
for ac power connections.
The
list that fol-
lows gives the circuit breaker
or
fuse and
disconnectrecommendedfor thelowpower
HT
transmitter line.
Transmitter Type
Circuit
Breaker
or
Fuse
&
Disconnect
HT250FM
IO
amp
HT500FM
15amp
HTlFM
3 °
~amp
The ac input wiring should
be
in
agree-
mentwithlocal electrical codes andcapable
of
supplying the transmitterpower require-
ments. An ac primary power disconnect
or
means to completely deenergize the
trans-
mitter primary circuit for servicing is nec-
essary.
If
the program leads must
be
routed
in close proximity to the ac power input
wiring, the program leads should be sepa-
rately shielded.
Agood ground at
FM
frequencies is man-
datory to keep stray
rf
currents to a mini-
mum.
RF
interference usually shows up
in
one
of
two ways, feedback
or
highnoise(in
some cases both). Even a small amount
of
non-shielded wire makes
a
very efficient
antenna for
FM
frequencies.
If
rf
from the
cabinet field is transferred to the audio
equipment,itcanberectified andmayshow
up
as
noise
or
feedback. A single common
ground pointfrom the transmitter base to a
good grounding system, such
as
a
water
pipe
or
actual
earth
ground
is recom-
2-1
WARNING: Dis
crnt1H'Ct
primary power prior to servicing.

www.SteamPoweredRadio.Com
mended.
A
grounding stud is located adja-
cent to the
AC
Input terminal board.
Installation is now complete and the sta-
tion transmission line may now be con-
nected at the 7/8 EIA flange (HT 1PM) or
N connector (HT 250 and
SOOFM)
at the
output
of
the directional coupler.
2.2.4.
Initial Checkout
I WARNING
DISCONNECT AND LOCK OUT STATION
PRIMARY POWER TO THE TRANSMIT-
TER.
Each transmitter is thoroughly checked
out during factory final test but adjustment
may be required during installation due to
shipping, variations in primary power, an-
tenna systems, or transmission line differ-
ences.
A
20kohm/voltmultimeter(Simpson 260
or
equivalent) may be required for the
checkout.
Before proceeding with the initial
FM
Transmitter testing, ~nsure that the
FM
Ex-
citer is completely installed, all parts are
back in position and correctly wired, the
transmitteris connectedto asuitable
rf
load,
and all signal monitors are connected. It is
fr
recommended that the ModulationMonitor
beconnectedto the BNCjacklocated
on
the
output side
of
the Lowpass Filter.
The complete transmitter should be in-
0 spected at this time. Use a vacuum cleaner
and thoroughly clean the interior
of
the
transmitter. Check the following:
2-2
c..--e1'hat
the primary power is connected to
the proper voltage taps but is switched
OFF.
i...-<That
the primary power is connected to
the
FM
Exciter rear plug.
LJ--That
the audio inputs are connected to
the
FM
Exciter.
........niat all connections at terminal boards
and components are tight.
---Removeany extrahardwarelying within
thecabinetand tighten all nuts and bolts.
'7
"
Check relay and solenoid armature op-
, eration manually. Ensure all have free,
unobstructed movement.
• That all wires and cabling are dressed
properly and secured.
• Refer to the Factory Test Data Sheets
supplied with the transmitter and adjust
thecontrols
as
indicated. Thetransmitter
was checked into a 50-ohm resistive
load at the Factory. Therefore, any sys-
tem with a mismatch may change the
settings. In thiscasethe recorded control
indications may not agree exactly with
actual operation.
det
the REMOTE/LOCAL switch to
LOCAL.
2.2.5. Connections to Remote Controls
The FM Transmitter may be operated by
remote control by installing a remote con-
trol system.
If
the transmitter is to be re-
motely controlled, it is importantto initiate
thorough inspection and maintenance pro-
cedures at the transmitter location. Installa-
tion
of
equipment to monitor temperature
and humidity at the remote transmitter site
is also recommended. Terminations pro-
vided in the FM Transmitter allow remote
control
of
the following transmitter func-
tions by connection to terminal boards on
the controller, A1TB1 and the Exciter,
A7A3TB1.Completeconnections to termi-
nal board
AlTBl
&/
or
A7A3TB1 are
shown inTable 2-1.
2.2.6.
External Fall-Safe Interlock Con-
nections
Remove the jumper between terminals 9
and 10 on terminal board
AlTBl
on the
Controller. Terminal board is located at the
upper rear
of
the transmitter
on
the read
of
the Controller chassis.
Connect the remote external fail-safe in-
terlock wiring to the terminals listed in the
preceding paragraph. A set
of
normally
closedcontacts is required when theremote
control is operational to operate the
ac
con-
tactor circuit.
If
a separate Stereo Generator is to be
used, there is rack space directly above the
exciter provided for this equipment. The
PGM cable between the Stereo Generator
and the exciter should be no longer that 24
inches.
2.2.7. EBS Connections
EmergencyBroadcastSystem(EBS)mut-
ing can
be
accomplished through the RF
MUTE line on the rear
of
the THE-1 Ex-
citer. This will
tum
the RF output to
OW
upon application
of
the proper signal. This
hasselectable logicbyjumper
A3Jl3
onthe
Exciter motherboard J13 (C-1) will select
ground to mute (open collector compati-
ble). J13 (C-2) will select 2-30Vdc tomute.
Refer
to
Exciter manual for further details.
To prepare wire, strip insulaiton
back
approximately
1/4
"
and twist strands back into their natural position.
A small flat blade screwdriveris an appropriate tool to use
to make the connection. To make connection, align wire
in
sideopening
"B"
anddepress clampdown from opening
"A"
with tool. Insert wire
or
component in opening
"B"
and
secure
by
withdrawing tool.
Figure2-1. Making Connections
to
WAGO Block
888-2312-001
WARNING: Disconnect primary power prior to servicing.

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TABLE 2-1. User /Transmitter Interconnections A1TB1
Terminal Nomenclature Signal
TBl -1
EXT IN1LOCK +, EXT IN1LOCK -Provisionfor an external TB1-2 interlockinputisprovidedbetweenterminals
1 and
2. This will inhibit transmitter operation if the circuit is broken. If this
provision is not used, a jumper must
be placed between terminals 1 and 2.
TBl-3
SPARE
Spare input. No connection.
TBl-4
SPARE Spare input.
No connection.
TBl-5
POWERFAULT
Provides external alarm of an output power fault set by R9.
TBl-6
BALANCE FAULT Provides external alarm
of an reject load fault set by R16.
TBl-7
SWRFAULT
Provides external alarm of VSWR foldback set by R64.
TBl-8
IN1LOCK FAULT Provides status
of the external interlock. If notused, a jumpermust be placed
between
TBl-1 and TBl-2.
TBl-9
FAILSAFE A continuously closed contact between this contact and
COMMON is re-
quired to activate the TRANSMITTER. This contact is maintained
as a
failsafe for remote operation.
TBl-10
COMMON Controller chassis ground.
TBl-11
EXT FORWARD Provides aremote indication of forward power. 1.8 Vde typical signal atrated
output power.
TBl-12
EXTSWR Provides a remote indication of SWR. 1.0 Vdc typical signal at 1.5:1 VSWR
at rated output power.
TBl-13
EXTV
Provides a remote indication of PA collector voltage. 4.1V typical signal at
50V.
TBl-14 EXTI Provides a remote indication of PA collector current. 1.8V typical signal at
40A.
TBl-15
SPARE Spare input.
No connection.
TBl-16
REMOTE ON Remote
TX ON command input. Connect to COMMON to activate. (Open
collector compatible.)
TBl-17 REMOTE OFF Remote
TX OFF command input. Connect to COMMON to activate. (Open
collector compatible.)
TBl-18
REMOTE RAISE Remote power raise command input. Connect to
COMMON to activate.
(Open collector compatible.)
TBl-19 REMOTE LOWER Remote power lower command input. Connect to COMMON to activate.
(Open collector compatible.)
TBl-20 REMOTE COMMON Controller chassis ground.
All controlfunctions must be connectedthroughN.O. contactstocommonatA1TB1terminal 20 on the Controller. Alarms andindicators
must
be connected through lamps or relays to +15 volts. Lamps, LED's, and relays should not require more than lOmA to operate.
888-2312-001 2-3
WARNING: Disconnect primary power prior to servicing.

www.SteamPoweredRadio.Com
SECTION Ill
OPERATION
3.1. Introduction
This section contains operating proce-
dures and information pertaining to identi-
fication, location, and function
of the
controls and indicators
on the HT line of
Solid State FM Broadcast Transmitters,
setup, and operation procedures.
3.2. Controls and Indicators
Figures 3-7, 3-9, and 3-11 show the loca-
tion
of all FM Transmitter controls and
indic1,1tors. Tables 3-4, 3-6, and 3-8 list all
ofthe controls and indicators with thefunc-
tion
of each item listed.
Controls andindicatorsfor the
FM Exciter
are described in the HARRIS FM Exciter
Technical Manual.
I lHl HARRIS:
I I
HT 250FM I
IB-/Wamll-
l~I ,j_-•-:-;-;-;i
0
-';" M ,:=!J, ,.a,+, 1,!,
0
l~l _j -
~D -,II. ,I,"'-' ~<i2.J
0 l.:'..._".-~
~
--
0 0
l~I
~; ·a_ - a1I
jgjgjc::Jj □ j
;; . ·-
0 =
~ -;;.-...:,w.:. ..... ----
0 Ul!.!..!'
.. ~U LoJ
0
~
---
0
~~~~~~~~~~~~~~~~~
0
0
i:_°J
~~~ 9P
0
I IBI-W¥l l$ 1
0 0
'\
•
\ \ 0
0 0
iZ:JOJ-OHil
2303-0'.!6
Figure 3-1. HT 250FMFront View Figure 3-2.
HT 250FM Rear View
Equipment
Refer To Page:
THE-1 Exciter See separate Technical Manu
al 988-2283-001
Controller !3-4
PA Amplifier 3-5
Table 3-1. HT 250FM Control and Indicator Index
888-2312-001
3-1
WARNING: Disconnect primary power prior to servicing.

www.SteamPoweredRadio.Com
I
(ID
HARRIS
I I
HT
:500F"M
I
a-111mm-
1~1-~_m
..
r~
0
o
li§c§§el#F§§§
0
l~I_J
--
-&&U
•
.,
0
~-~
i.j)'"Qlf"@.J
~
crlfmlll-
0 0
l~I
r;-:;---:-;;i
1~61!u!rn!1l!i1
-=.
·-
0
lll-&,JJ,W.i'i.-----
0
Y..Y
~ff:,.~
Y..Y
l+l
0
~
---
0
~~~~~~~~~~~~~~~~~
0
0
i!
....
°-1
~!±J
f
0
Oiuim]
0 0
'
\ 0
0 0
Q30:l-020 2303-006
Figure3-3.
HT
S00FM
Front
View
Figure
3-4.
HT
S00FM
Rear
View
Equipment Refer
To
Page:
THE-1
Exciter See separate Technical Manual 988-2283-001
Controller 3-4
PAAmplifier
3-5
Table 3-2.
HT
S00FM
Controls
and
Indicators
Index
3-2 888-2312-001
WARNING: Disconnect
primary
power
prior
to servicing.