REL 518-D User manual

INSTRUCTION MANUAL
FOR
MODEL 518(D)-DL
ONE THOUSAND WATT
FREQUENCY MODULATED
BROADCAST TRANSMITTING
EQUIPMENT
RADIO
ENGINEERING
LABORATORIES

INSTRUCTION MANUAL
FOR
MODEL 518(D)-DL
ONE THOUSAND WATT
FREQUENCY MODULATED
BROADCAST TRANSMITTING
EQUIPMENT

TABLE OF CONTENTS
MODEL 518 INSTRUCTION MANUAL
SECTION I. INSPECTION OF RECEIVED MATERIAL - CLAIMS FOR BREAKAGE IN SHIP-
MENT
SECTION II. GENERAL DESCRIPTION OF EQUIPMENT
SECTION III. ASSEMBLY AND INSTALLATION
SECTION IV. THEORY OF OPERATION
SECTION V. PRELIMINARY ADJUSTMENTS AND OPERATION OF THE EQUIPMENT
SECTION VI. MODULATOR AND POWER AMPLIFIER ADJUSTMENTS
SECTION VII. CONSOLIDATED PARTS LISTS
SECTION VIII. MAINTENTANCE OF EQUIPMENT - ORDERING SPARE OR REPLACEMENT PARTS
PROCEDURE FOR RETURN OF MATERIAL
ACCESSORY DATA SUPPLIED 'dITH THIS MANUAL IN REAR COVER POCKET: -
6 COPIES DEFECTIVE MATERIAL NOTIFICATION FORM
6 COPIES DEFECTIVE MATERIAL RETURN FORM
IN SEPARATE DRAWING FOLDERs-
TITLE NUMBER
INSTALLATION DRAWING T-68
STATION WIRING DIAGRAM B-654
MODEL 518 WIRING DIAGRAM SS-635
CONTROL CIRCUITS - ACROSS THE LINE DIAGRAM B-629
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SECTION 1
INSPECTION OF RECEIVED MATERIAL
RE-ASSEMBLY OF PARTS REMOVED FOR
SHIPMENT - CLAIMS FOR BREAKAGE
IN SHIPMENT.
1. UISPECTION OF RECEIVED MATERIAL
Received material should be carefully inspected at the time of uncrating for
evidence of damage or breaking due to careless handling in transit. Care and good
sense should be used in the process of unpacking or uncrating the equipment. Hasty
use of improper tools such as crowbars, etc., may easily result in damage to the
enclosed equipment. Be sure to note and follow externally marked instructions such
as, "This End up" or "Oper. This End ", etc. All equipment is carefully packed at
the factory to insure safe delivery with reasonably careful handling. When remov-
ing items from packing material check item by item against the enclosed pecking
list for errors or short shipment.
2. CLAIMS FOR BREAKAGE IN SHIPMENT
In cases of damage to equipment due to faulty handling in shipment, notify car-
rier immediately leaving broken or damaged item or items exactly as found in pack-
age. Do not destroy or remove any of the wrappings or protective material involved
in the wrapping of the damaged item. Carrier companies will not accept claims for
"Damage in Shipment" unless they can inspect the damaged item and its associated
packing material. Claims must usually be made within five days of receipt of ship-
ment.
Section 1 - 1

SECTION II
GENERAL DESCRIPTION OF EQUIPMENT
A. General Description
The REL Model 518 FM Broadcast Transmitter is designed to deliver 1000 watts
of radio frequency power at any selected frequency from 88 to 108 megacycles. Modu..
lation is accomplished by the Armstrong Dual Channel Phase Shift method, the modula-
tor being an integral part of the transmitter.
The equipment is completely housed in a vertical steel cabinet normally finished
in two tone green lacquer with chrome trim. The cabinet is 84" high, 40" wide and 36"
deep.
Various functional units in the equipment have been sectionalized on individual
chassis. Each separate chassis is hinged at one end and may be swung out for conven-
ient inspection or maintenance work.
B. Primary Power Connections
Refer to drawing B-654 which shows details of the transmitter input terminal
boards and connections.
208/230 volts, 60 cycles single phase should be terminated at the terminals mark-
ed A, B, using #10 AWG wire or larger. Primary load for rated output is approximately
3700 volt amperes at 890 power factor. 110 to 120 volts single phase should be connect-
ed to terminals 3 and 54 using #12 AWG wires for powering the convenience outlet
and interior lighting.
A good low resistance ground should be connected to the terminal marked "0" on the
terminal board which is located on the left vertical frame member just inside the lower
front panel.
C. Output Transmission Line Connections
The equipment is supplied for operation with a single 7/8" coaxial transmission
line which enters the top of the cabinet. Location of this point may be determined by
reference to outline drawing T-68.
D. Accessory Data
A 600 ohm balanced audio input line must be connected to the twin conductor jack,
which is located behind the lower front panel on the right hand corner post. This line
should be of the insulated shielded twisted pair type and should avoid proximity to high
level AC lines. Since there is not pre-emphasis included in the transmitter standard 75
micro second pre-emphasis should be included at some point in the audio equipment.
A coaxial jack is provided beside the audio input jack for connecting the monitor
to the sampling loop in the power amplifier cabinet.
Section II - 1

SECTION III
ASSEMBLY AND INSTALLATION
A. After the equipment has been unpacked remove all panels to permit easy access
to the interior. A considerable amount of packing material shipping straps and
braces will be found within the equipment, notably in the high voltage supply re-
lay panel, modulator power supply, and power amplifier compartment. This material
should all be removed and the supported parts carefully examined for any damage
which may have occured while the equipment was in transit.
B. After the equipment has been located in its final position the power lines may
be connected. Provision has been made in the cabinet design to permit cable en-
trance either through exposed conduit or concealed floor trench type wiring. A "TEE"
shaped duct is built into the base of the transmitter which allows conduit entrance
via either side near the front or through the rear center. The location of these
knockouts is indicated on the installation drawing T-68. In addition an 8" x 2" open-
ing covered with a removable plate is provided for entrance of cables via a floor
trench. If used, this palte should be removed and holes cut to permit passage of the
cables. Unless the plate is reinstalled, an air leak will result, thus destroying
the effectiveness of the intake air filter.
Primary power connections are made to terminals "A" and "B ". The auxiliary
lighting circuit connections are connected to terminals 53 and 54.
C. The output transmission line connections may now be made up.
D. Connect the audio input line and the monitor by means of the plugs which are pro-
vided in their respected jacks.
E. Install plug in resistors which are located as noted below:
SYMBOL NO. STOCK NO. RESISTANCE LOCATION
R-800 R-5104 or R-5273 200,000 ohms Resistor panel left side, bottom
row, center.
R-801 R-5105 5 neghom Resistor panel, bottom row, rear.
R-803 R-5097 or R-5269 500 ohms Resistor panel, bottom row, front.
R-805 R-5109 or R-5271 250 ohms Resistor panel, middle row.
R-806 Same as R-805 Resistor panel, middle row.
R-807 R-5321 500 ohms Bottom of grid circuit.
R-808 Same as R-805 Resistor panel, middle row.
R-809 Same as R-805 Resistor panel, middle row.
R-810 R-5321 500 ohms Below PA tube deck, left.
H--811 R-5269 500 ohms Resistor board, lower right side.
R-812 Same as R,-811 Resistor board, lower right side.
R-818 R-5336 1250 ohms Resistor panel, left side, top row,
rear.
R-819 B-5337 2000 ohms Resistor panel, left side, top row,
front.
R-820 R-5321 500 ohms Below PA tube deck, right.
Section III - 1

F. Install all tubes. Pilot lights and glass fuses are shipped in their res-
-oective sockets.
G. There are five lumiline lamas to be installed. Two are used to illuminate
the meter panel and the sockets for these will be found directly below the meters.
Two are used inside the power amplifier compartment and operate when the compart-
ment door is opened. One is located inside the plate compartment on the top front
Hanel. The other is located under the PA tube deck just inside the front flange.
The fifth light is located on the rear of the same cornerpost which supports the
audio input jack.
Section III - 2

SECTION IV
THEORY OF OPERATION
A. POWER CONTROL CIRDUIT
1. General
The power controls are designed to provide either complete manual or semi-
automatic control with facilities provided for remote control of the application
of power to the various stages, proper protection of equipment in the case of over-
loads, and reasonable time delays between the application of filament and plate volt-
ages. All cabinet doors with the exception of those over the modulator compartment
and the main front doors, are interlocked for the protection of personnel.
2. Primary Power Source
The main operating power is completely supplied by a 208/230 volt (plus or minus
5%) 60 cycles, single phase source. All filament transformer primary voltages are con-
trolled by the variable auto transformer YR-800 which is located on the right hand con-
trol panel, and should be adjusted to Produce a reading of 5.0 volts on the front panel
"FILAMENT VOLTAGE".
3. Control Circuits
The schematic diagram of the control circuits is shown on drawing SS-638. A func-
tional across the line diagram is shown on drawing B-629 which will be useful in under-
standing the sequence of control operation.
The STANDBY switch 5808 should always be on, except for maintenance work on the
standby circuit. Even so, the input side of 5808 and the main circuit breaker, K800,
will be energized, hence it is advisable to open the main safety switch which powers
the entire transmitter when maintenance work is required. When 5808 is closed, trans-
former T703 is energized through fuse F806 and protective resistor R-715. The second-
ary of T703 operates the crystal heater when the transmitter is off the air. The stand-
by fuses 7807 and F808 provide protection for the standby and blower shut down circuits.
With all of the switches except the STANDBY SWITCH S808 open, the first switch to
be closed is the PRIMARY POWER circuit breaker K800. The coil of the blower relay K806A
is energized through the standby fuses F807 and F808 closing contacts K806B, K806C, and
K806D. The blower time delay relay K807 is also energized through the normally closed
contact K801C of the time delay relay K801. However relay K807 will not operate at this
time since its normal time delay is 2 minutes, and contact K8010 will open 60 seconds
after switch 5800 is closed. Contacts K8060 and K806D apply power to the blower B800
through the thermal eliment K806E, and also to the blower pilot light, I803. The meter
lights 1805 and I806 should come on when K800 is closed.
When the FILAMENT switch 5800 is closed and the blower B800 has reached its Proper
speed, the air switch 5807 will be closed thus energizing the filament variable auto trans_
former YR800 which in turn controls the voltage on T700 through F801 which supplies 6.5
volts AC for the modulator AC filaments; T701 through F802 which supplies 6.6 volts DC
for the modulator DC filaments; K700 which switches the crystal heater from 6.0 volts AC
standby to 6.6 volts DC operate; T800 through F803 which controls the screen the bias
supply filaments; T801 supplying the power amplifier filaments at 5 volts which is read
on the FILAMENT VOLTAGE meter; T804, T805 and T806 which supply the high voltage rectifier
filaments; K801 the rectifier tube time delay (60 seconds) which withholds application of
high voltage until the rectifier tube cathodes are hot and finally I800, the filament
pilot light.
Section IV - 1

60 seconds after the closing of the FILAMENT switch S800, the time delay relay
K801 will operate, closing contact K801B and opening contact K8010. If all door inter-
locks are closed and the MODULATOR HIGH VOLTAGE switch is closed, then the coil of re-
lay K802A will be energized closing contacts K802B and K8020. K802B, when closed, applies
power to the modulator high voltage transformer T702 and the modulator high voltage pilot
light I801, through fuse F804. K802C when closed energizes the high voltage recycling
time delay (5 seconds) through the overload relay contact K805B, and the bias high volt-
age transformer T802 through fuse F805.
After 5 seconds from the time the MODULATOR HIGH VOLTAGE switch S801 was closed
time delay relay K803 will operate, closing its contact, K803B. Then if the HIGH VOLT-
AGE switch S805 is closed, the PA high voltage relay K804 will be energized, closing con-
tacts K804B and K8040 through which power will be applied to the primary of the high volt-
age transformer T803 through the tap changing switch S818, and to the high voltage pilot
light I802. The closing of the power amplifier high voltage switch completes the cycle
of manual operation and the equipment is ready for transmission provided that the eouip-
ment has been previously adjusted for proper voltages and the tuning controls were pro-
perly set. The switching controls are designed so as to control the cycle of operation
at any stage desired. If any of the control switches S-800, S-801 or S-805 are opened,
the cycle of operation will automatically continue to the stage controlled by the particu,
lar switch that is opened and then stop. Further continuation of the operating cycle re-
quires the closing of the switch or switches that follow.
The manual "OFF" operation is performed in the reverse sequence of the "ON" operation,
the power amplifier HIGH VOLTAGE SWITCH S-805 is turned off which removes the power ampli-
fier high voltage then the modulator high voltage switch S-801 is turned off, followed by
the turning off of the filament power switch S-800 and finally the primary power circuit
breaker, K-800.
If for any reason, by manual "OFF" operation or by a heavy overload, the overload
breaker K -800 is opened, only one of the parallel sources of supply for the blower relay
coil L-806A is removed and contacts K-8060 and K-806D remain closed. The power supplied
through these contacts will keep the blower B-800 operating. At the same time that the
circuit breaker K-800 is opened, power is removed from relay coil K-801A, thus closing
contacts L-8010. Contact K-8010 energizes the blower time delay relay K-807, and after 2
minutes, the normally closed contact K-807B opens thus removing the second of the two
parallel sources of power for relay K-806A. This relay opens contact K-806B which turns
off the blower B-800 and the blower pilot light I -803.
Section IV - 2

CAUTION
The standby crystal heater switch S-808 should never be turned off until the
blower B-800 has stopped.
Assuming that S -808 is "on" in the standby position, semi-automatic operation
of the control circuit is obtained by turning on all switches (S-800, S-801, S-805)
except the main PRIMARY POWER circuit breaker K-800. Then when K-800 is closed, the
relays function as previously described and after approximately 65 seconds, the
equipment is ready for transmission. The "stop" operation is performed by simply open-
ing circuit breaker K-800. Approximately 2 minutes after the "stop" operation, the
blower B-800 will stop and the standby crystal heater power will be the only power on.
Care must be exercised when working near switch S-808.
In the power amplifier H.Y. supply, an automatic reset overload current relay
K-805 protects this stage from overloading. Relays K-802, and K-803 and K-804 will
function as previously described under normal conditions after relay K-805 has been
opened and automatically closed.
No provision is made to limit the number of recycling periods in the event of
serious overload or short circuit in the high voltage circuit. Therefore if recy-
cling persists, the equipment should be turned off and the source of trouble deter-
mined. The PRIMARY POWER circuit breaker K-800, which is a manual reset overload
breaker protects the entire unit and will open only under much heavier overloads than
the other overload rely K-805. Caution should be taken before closing K-800 after an
overload.
Section IY - 3