Kenwood TL-922A User manual

QKENWOOD
LINEAR AMPLIFIER
Model TL-922A
INSTRUCTION MANUAL

AFTER UNPACKING
It is advisable to save all original packing cartons (inner and
outer) to protect your valuable Linear Amplifier from
damage should you wish to transport it for remote opera-
tion or ship it for after-sales service.
The following explicit definitions apply in this manual. Be
sure to read these definitions:
NOTE = If disregarded, inconvenience only — no
damage or personal injury.
CAUTION = equipment damage may occur, but not
personal injury.
WARNING = personal injury may occur — do not dis-
regard.
CONTENTS
TL-922A SPECIFICATIONS . .
SECTION 1 FEATURES .. . .
SECTION 2. PREPARATION FOR USE
2.1 Accessories
2.2 Installation of Power Tubes
2.3 General Tips on Installation
2.4 AC Power Source
2.5 Line Voltage Change
2.6 Power Cable
2.7 Exciter
2.8 Antenna
2.9 Interconnection
2.9.1 Grounding
2.9.2 Cable Connection
SECTION 3 CONTROLS AND THEIR FUNCTIONS . 9
3.1 Front Panel
3.2 Rear Panel
SECTION 4 OPERATION ...... wee ee ee eeeee 11
4.1 Prechecks
4.2. CW Operation
4.3 SSB Operation
4.4 RTTY Operation
4.5 Setting the ALC ADJ Control
4.6 Adjusting the RF Output Meter
4.7 High-Voltage Transformer Protection
4.8 Carrying Your TL-9224
SECTIONS CIRCUIT DESCRIPTION......... 13
5.1 Linear Power Amplifier
5.2 Power Supply
5.3 Fan Motor Delay Stop Circuit
5.4 Meter Drive Circuit
5.5 Spark Suppressor
CAUTION
Read Operating Manual Section 2 before proceeding to
unpack and assemble your amplifier.
WARNING
LETHAL VOLTAGES PRESENT.
SECTION 6 MAINTENANCE...............- 15
6.1 Internal Cleaning
6.2 Replacing Power Fuses
6.3 Replacing Power Tubes
6.4 Input Matching Circuit
SECTION 7 TROUBLESHOOTING HINTS .
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ILLUSTRATIONS
Fig. 2-1 Upper Case Cover Assembly/
Disassembly ............. 5
Fig. 2-2 Correct Power Tube Handling 5
Fig. 2-3 Parasitic Suppressor Coil Mounting 6
Fig. 2-4 Input Voltage Terminal Boards 7
Fig. 2-5 Power Cable Color Code . . 8
Fig. 2-6 Exciter Connections for RL and ALC
Controls ......... oii eee » 8
Fig.
2-7
Interconnection
of
the
TL-922A
......
8
Fig. 3-1 Front View....... beciegtsade hice) 8
Fig. 3-2 Rear View Cees eae eehae es . 10
Fig.
5-1
Linear
Power
Amplifier
Circuit
.......
13
Fig. 5-2 Transformer Primary Current Flow..... 14
Fig. 5-3. Fan Mogpr Delay Stop Circuit ........ 14
Fig. 5-4 Meter Drive Circuit................ 14
Fig. 7-1 Packing for Shipment . 17
Fig. 7-2,3Top, Bottom Views 18
TABLES
1.
Front Panel
Controls
Set-Up
..............
11
2.
Tune
and
Load
Initial
Settings
.............
11

Transmit Frequency Range:
Excitation Energy Required:
Mode and Duty Cycle:
Rated Plate Input:
Plate Voltage: (at No signal)
Circuit Type:
3rd Order Intermodulation Distortion:
Input Impedance:
Output Impedance:
Cooling:
Interlock Safety Features:
Thermal Protector:
Fan Motor Delay Stop Time:
ALC:
Power Tubes Used:
Semiconductors:
Power Requirements:
Cables Supplied:
Dimensions:
Weight:
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TL-922A SPECIFICATIONS
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160m through 15m Amateur Bands
80 W nominal, 120 W maximum
SSB, continuous for 30 minutes.
CW and RTTY, key-down continuous for 10 minutes.
2 kW P.E.P. SSB, 1 kW CW RTTY
3.1 kV SSB, 2.2 kV CW RTTY
Class AB2 grounded grid linear amplifier
Below —30dB.
50 2, unbalanced at better than 1.5 SWR
50 to 75 2, unbalanced.
Forced Air.
Primary high voltage circuit cut-off.
Secondary high-voltage circuit grounding.
Locks out transmit relays if H.V. power transformer overheats.
140 + 30 seconds. (at room temperature)
Negative going, adjustable threshold -8V DC maximum output (typical).
Eimac 3-500Z, two pieces
Diodes, 18 pieces
Zener diode, 1 piece
120V, 28A; 240V, 14A; 50/60Hz; for maximum SSB input.
Signal cable (coaxial) with UHF-type connector, 1.5m.
Control cable, 1.5m.
390mm x 190mm x 407 mm (15-3/8 x 7-1/2 x 16”)
Net 31 kg (68 Ibs.)
Shipping 38 kg (83 Ibs.)
The above specifications are subject to change without notice due to technical im-
provement.

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The TL-922A is a Class AB2, grounded grid linear
amplifier developed by Trio-Kenwood through ad-
vanced high-power technology using two high-per-
formance Eimac 3-500Z power tubes. It covers all
bands 160 m through 15 m for SSB, CW and RTTY
modes of operation.
Unprecedented Reliability
The TL-922A is designed to provide stable, high RF
output power for extended periods of continuous use.
Engineered with Trio-Kenwood’s advanced circuit and
mechanical technology, the TL-922A employs two
rugged 3-500Z power tubes to their full advantage.
Low Intermodulation Distortion
Intermodulation distortion (IMD) is minimized
through the use of negative R.F. feedback.
Quick Turn-On
Warm-up is not necessary. The 3-500Z tubes are fast
heating.
Full Safety System
To protect you against any possible high voltage elect-
ric shock, your TL-922A has a double safety system
comprised of interlocking switches. One interrupts
the high voltage primary circuit while the second
directly grounds the secondary high voltage circuit.
Also provided are bleeder resistors for discharging the
high voltage capacitors and “DANGER” warnings at
high voltage positions. Please observe all warnings,
they are for your protection.
Newly-Developed Fan Motor Delay Stop Circuit
To reduce power tube deterioration, your TL-922A
has a newly-developed fan motor delay-stop circuit
comprised of a thermal delay relay. The cooling fan
will normally run for 140 seconds (Typ) after power
is removed from the unit and will measurably ex-
tended tube life.
Mode Switch for Efficient Linear Operation
MODE switching is provided to select between the
SSB Mode for the maximum PEP output with good
SECTION 1. FEATURES
sustenance canna ta
10.
11.
12.
13.
linearity, and the CW Mode for low power consump-
tion and heat generation during extended periods of
operation.
Linear Amplification Control Switch
This switch is capable of setting your TL-922A in the
straight-through state irrespective of the standby
control on the exciter.
Variable Threshold Level (ALC Detector)
The ALC circuit will accommodate exciters of 80 w
to 120 w (nominal) by varying the ALC threshold
level. This effectively prevents overdriving the final
power tubes, limiting the Amplifier to its linear range
and guaranteeing low distortion at maximum power.
Two Panel Meters
In adjusting or monitoring your TL-922A, one meter
always indicates the (Ip) plate current; while, with the
other, you may read (Ig) grid current, (RF) relative
output, or (HV) high voltage. This facilitates ease of
operation of your TL-922A.
Rigid Mechanical Structure
The die-cast side panels effectively support the weight
of the amplifier against shocks and jarring during
transportation. Recessed side panel handles are pro-
vided so the Amplifier can be easily carried.
Vernier Plate Tuning Dial
The PLATE tune dial is equipped with a reduction
gear that facilitates easy tuning, particularly for the
higher bands. It also effectively prevents accidental
miss-tuning during operation. Controls and panel
arrangement, designed to human _ engineering
standards, provide superior ease of operation.
Neat, Contemporary Appearance
Mechanical arrangement and sophisticated design to
match any Trio-Kenwood transceiver or transmitter.
Your TL-922A can also be used as a high-quality,
general purpose Amateur band linear amplifier with
any exciter capable of 8OW to 120W RF output.

2.1 ACCESSORIES
Carefully unpack your TL-922A Linear Amplifier and
check that it is supplied with the following accessories.
1, Instruction manual B50-2587-00 1 copy
2. Coaxial cable, 1.5m, with UHF-type
connectors X42- 1100-00 1 piece
3. Control cableW/8Pin Plug 1 piece
(For TS-520, TS-820 Series)
X42-1110-10
4. Control cable W/7 Pin Plug 1 piece
(For TS-120, TS-130, TS-180, TS-430,
TS-530, TS-830, TS-930 Series) X42-1110-11
5. Spare fuse, 15A FO5-1533-05 2 pieces
6. Extension foot JO2-0049-14 2 pieces
7. Screws, 4 x 12mm long N30-4012-46 2 pieces
8. Plate cap FO2-0407-04 2 pieces
9. Parasitic suppressor coil, right hand 1 piece
L39-0401-05
10. Parasitic suppressor coil, left hand 1 piece
L39-0402-05
11. Screw, 3 x 6mm long N30-3006-46 4 pieces
12. Plain washer N15-1030-46 4 pieces
13. Spring washer N16-0030-46 4 pieces
2.2 INSTALLATION OF POWER TUBES
To protect the power tubes in your TL-922A against
vibration and shock during transport, they were packed
separately from the amplifier. For insertion, follow the
procedures below. Prepare the following mounting
hardware and tools:
Mounting Hardware
Power tube, 3-500Z 2 pieces
Plate cap 2 pieces
Parasitic suppressor coil, right hand
and left hand 1 piece each
Screw, 3 x 6 mm long 4 pieces
Plain washer 4 pieces
Spring washer 4 pieces
Tools
Phillips screwdriver 1 piece
Small standard screwdriver 1 piece
NOTE: A parts tray to prevent loss of metric hardware is
helpful.
WARNING: Before proceeding, make sure that:
The power cable is NOT plugged in the wall out-
let. The METER switch is at the HV position
and the multimeter reads OV.
Proceed as follows: (Refer to Fig. 2-1)
1. Remove the four 4 mm Phillips screws holding the
upper case cover.
2. Remove the upper case cover.
3. Remove the four 3 mm self-tapping Phillips screws
and four flat head self-tapping Phillips screws holding
the inside shield on the power tube enclosure.
Se ee
SECTION 2. PREPARATION FOR USE
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Remove the shield plate.
5. Take the tubes out of their case (Refer to Fig. 2-2). In
handling, be sure to hold them by the glass envelope,
not the plate cap.
6. Carefully index the pins of each tube into its socket
and insert gently without excessive force.
INSERT UPPER 4mm
CASE COVER r ia v ical
LEADING EDGE
INTO FRONT |
PANEL TOP LIP
HIGH VOLTAGE |
PRIMARY PROTECTION
SWITCH PLUNGER }
3mm FLAT HEAD Z
SELF-TAPPING \, wT | ¥
SCREW (4 PCS) B an
cree
INsiDe 42
HIGH VOLTAGE | 184
! : [SHIELD PALTE
SECONDARY
PROTECTION
SWITCH |
PLUNGER.
UPPER CASE Figure 2-1
COVER
INSERT
Upper
Case
Cover
D ata \2 Assembly/Disassembly.
SWITCH USE #2 Phillips
PLUNGER Screwdriver.
Figure 2-2 — Correct Power
Tube Handling

CAUTION
Particular care should be taken not to strike and
break the glass tubes during installation. Tube break-
age due to negligence is not warranteed
th (Refer to Fig. 2-3) Temporarily fix each parasitic sup-
pressor coil on the plate cap with the letter “R’” or “L”
facing up. At this time, do not tighten the 4 mm screw
and spring washer, but snug them so the coil may be
adjusted.
8. Mount the plate cap with parasitic suppressor coil on
each tube observing the right hand and left hand coil
designations. If the screw holes do not align, shape
the coil by slight bending or extending by hand for
precise installation, keeping the coil below the level
of the plate cap.
CAUTION: Particular care should be exercised in not
applying excessive force to the tubes.
9. Carefully tighten the screws at each end of the coil
while holding the plate cap by hand.
10. Tighten the plate cap screw using the small standard
screwdriver.
11, Check to assure correct installation by reference to
Fig. 3-3.
NOTE:
1: Before installation, check each parasitic suppressor coil for
good alignment to prevent the application of excessive force
to the tubes.
: Letters “'R’ and “’L” on the coils should face up.
: Temporarily install each coil on their plate caps before final
tightening. Use # Philips screwdriver.
Figure 2-3 — Parasitic Suppressor Coil Mounting
Tube Installation Checkout
1. To avoid damage necessitating tube replacement,
please check:
a. Power tubes are free from scratches or other
physical defects.
Tubes are fully inserted into their sockets.
Plate cap screws tightened securely.
d. — Screws at both ends of the parasitic suppressor
coils are tightened securely.
e. Washers, screws, drivers and any other unneces-
sary material is not left inside the unit.
ra Refer to Fig. 2-1. The inside shield plate includes the
high voltage secondary protection switch plunger (a
bakelite bar.) Position the plate so that the plunger will
securely engage the spring plate for ungrounding the
plate high voltage.
3. Install the upper case cover with its leading edge in-
serted (approximately 1 mm) into the front panel lip.
This cover has the high voltage primary protective
switch plunger. Position the cover so the plunger will
engage the microswitch.
os
2.3. GENERAL TIPS ON INSTALLATION
Install in a dry, well-ventilated area, shaded from direct
Sunslight. Your TL-922A must have a minimum
clearance of 15 cm to the rear to allow hot air at 50 to
70°C to exhaust.
Choose an operating position capable of safely supporting
the weight of the TL-922A (31 kg), plus all the other
station equipment.
Level your TL-922A in operation. The heated electrodes in
each power tube will be distorted by gravity resulting in
shortened service life, if slanted beyond 10°.
2.4 AC POWER SOURCE
Use an AC power line having sufficient current capacity
or the performance of your TL-922A will be adversely
affected by inadequate line regulation. In the worst case,
do not deviate more than +10% from the rated input
voltage for which your Amplifier has been set.
2.5 LINE VOLTAGE CHANGE
WARNING
DISCONNECT THE AC INPUT POWER CABLE
FROM THE TL-922A BEFORE PROCEEDING.
The input voltage can be changed to either 240V or 120V as
required, by changing the power transformer input links
located in the duct on the rear panel.
NOTE: The TL:922A was factory set in the 240V position.

To change link positions, remove the access cover by the
two black snap fasteners. Loosen the screws holding the
shorting bars, a few turns only. (Do not loosen excessively
as they could drop into the Amplifier.) Draw each shorting
bar upward for removal. Replace the shorting bars for the
operating voltage desired as illustrated in Fig. 2-4. Tighten
firmly. Also, be sure to tighten the screws from which the
shorting bars were removed.
NOTE: Fuses need not be changed in current rating when
the input voltage is changed.
CAUTION: Excess force may break the terminal strip.
2.6 POWER CABLE
The power cable supplied with your TL-922A has no plug
at its end. Connect a plug mating with the wall outlet.
The blue and brown leads are power, the green lead ground
as illustrated in Figure 2-5.
2.7 EXCITER
An HF Amateur band SSB or CW transmitter or transceiver
having an RF output impedance of 502 and output power of
80W to 120W is sufficient to drive the TL-922A. Exciter
output exceeding 120W will cause overdrive, resulting in
shortened power tube life and distorted output. To limit the
power level above 120W, use an exciter having an external
ALC input terminal.
CAUTION: BE SURE TO TIGHTEN ALL
LOOSENED SCREWS.
Use # Philips screwdriver.
Spare shorting bars
are secured at terminals 3 and 4.
a: 240V setting
b: 120V setting
Figure 2-4 — Input Voltage Terminal Boards
Trio-Kenwood's transceivers Series TS-930, TS-830,
TS-820, TS-530, TS-520, TS-430, TS-180, TS-130,
TS-120 and TS-900 and transmitters Series TX/T-599
are all suitable exciters and will match the TL-922A in de-
sign as well as appearance.
2.8 ANTENNA
Your TL-922A requires an antenna having a 50 to 752
impedance and providing it is:
(1) Rated for 2 kW P.E-P input power
(2) and, exhibits a low standing-wave ratio (SWR)
Desired SWR is 1.5 to 1. or less. A higher SWR, 2 or
3 to 1, may cause difficult matching with your TL-
922A. Excessive SWR could melt the coaxial cable
and antenna. To protect your TL-922A against
adverse SWR effects, use an antenna tuner. Note that
feeder radiation due to mismatching will cause TVI,
BCI, or similar RFI.
BLUE
BROWN
TO
240/120V
LINE
TO GROUND
GREEN
Figure 2-5 — Power Cable Color Code
EXCITER
TbooA
TRANSMIT
|
RL
CONTROL!
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RELAY POWER
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SOURCE
RECEIVE
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ALC
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CONTROL
ALC
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Figure 2-6
Exciter Connections for RL and ALC Controls.

2.9 INTERCONNECTION
2.9.1 GROUNDING
Connect the GND posts of the TL-922A and
exciter
RFI.
to prevent possible electric shock and
The wire used should be as thick and
short as possible and run to a good earth ground.
2.9.2 CABLE CONNECTION
Interconnect your TL-922A and exciter with the
supplied cables as illustrated in Figure 2-7.
NOTE:
If you use an exciter of another brand,
replace the supplied connector with one
appropriate to your exciter. The exciter
used must accept the negative-going ALC
voltage from the TL-922A.
(The ALC output at no signal input is
normally positive when not connected to
the exciter.)
The RL, or standby control, in the exciter must be
switched to ground in transmit mode, as illustrated
in Figure 2-6.
NOTE: Use RG-8/U, RG-11/U or heavier as
antenna cable.
NOTE: If an SWR meter is connected between
the TL-922A and the exciter, total co-
axial cable length must not exceed 1.7 m.

7 8 9 1
10
Figure 3-1 Front Panel View
3.1 FRONT PANEL
1.
IP Meter
The IP meter reads the plate current flowing through
the power tubes.
ON AIR Indicator
The ON AIR indicator lights up in the on-the-air,
or transmit MODE.
PLATE Tuning Control
This control permits you to tune the plate circuit to
the desired transmit frequency, and is equipped with a
reduction gear for easy tuning.
Multimeter
The Multimeter can read the Ig (grid current), RF
(relative power output), or HV (plate voltage) as
selected by the METER switch
STBY Indicator
With the unit turned on, shows unkeyed or receive
state.
LOAD Control
Impedance matches the pi network to the antenna.
POWER Switch
A double pole switch completely disconnects the AC
input from the transformers.
MODE Switch
Set for SSB or CW. For RTTY operation, set the
switch to the CW position.
10.
11,
METER Switch
Selects Ig (grid current), RF (relative power output), or
HV (plate voltage).
BAND Selector
Set for the Amateur band in which operation is
desired.
LINEAR Switch
In the STBY position, the exciter runs straight
through. In the OPERATE position, the Amplifier
automatically keys with the exciter.

5 6 7 10 8
Figure 3-2 Rear Panel View
3.2 REAR PANEL
1.
Cooling Fan
The Cooling Fan cools the power tubes and effectively
keeps the inside temperature from increasing. Be
careful of hot air (50° to 70°C) at the exhaust port.
Line Voltage Change Terminals
These terminals are located behind the rear cover,
which is removed by pulling the two snap fasteners.
For input voltage change, please refer to Section 2.5.
Serial No. Plate
This plate is stamped with the Serial Number of your
TL-922A.
RF METER Control
This control is used to calibrate the RF output read-
ing. For calibration, see Section 4.6.
ALC ADJ Control
This control is used to adjust the ALC voltage. For
adjustment, see Section 4.5.
ALC OUT Jack
This jack feeds the ALC voltage out.
RL CONT Jack
This jack inputs the transmit-receive relay switching
ground from the exciter
10.
11.
12.
RF INPUT Connector
This UHF-type connector inputs the RF signal fed
from the exciter. Use the supplied cable.
RF OUTPUT Connector
This UHF-type connector feeds the RF output to
the antenna.
GND Post
Use this post to ground the TL-922A to your exciter
and station ground.
FUSE Holders (2)
Each contains a 15 A fuse. If either or both fuses are
blown, determine the cause before replacement.
POWER Cable
AC power is supplied to the amplifier by a three-wire
cable. (See section 2.6)