33
Synopsis
Checkout of the modified amplifier will be performed in a series of stages. For each of
these steps, AC mains electrical power will be applied to the amplifier. However, It is
IMPERATIVE
that all safety precautions be observed due to the presence of lethal voltages!
DO NOT TOUCH ANYTHING within the amplifier while it is plugged into the AC mains
or whenever High-Voltage is present, such as from the anode High-Voltage power supply!!!
1. Ensure the top outer cover is removed from the amplifier (this should ensure the HV
transformer will not be energized).
2. Place the amplifier upside-down on the workbench.
3. Install the AC mains fuses.
4. Place the amplifier “POWER” switch to the
OFF
position.
5. Set the amplifier “METER” switch to the
HV
position.
6. Set the amplifier “LINEAR” switch to the
STBY
position.
Step-Start and LED Checkout
This test will confirm correct operation of the Step-Start circuit as well as the proper se-
quencing of the
ON AIR
and
STBY
lights.
Whenever the amplifier is switched
On
, the AC mains current flow is limited briefly
by the two power resistors on the Step-Start PCB. After a brief interval (approximately 2
seconds), the Electronic Bias PCB circuitry will energize the Step-Start Relays, causing the
relays to close, no longer restricting input current. When this occurs, the meter illumination
will increase in brightness and the user should hear the relays close. All of this should occur
within the first 2-3 seconds of operation. If the Step-Start Relays do not close within this
interval, it indicates a problem that must be solved before proceeding.
Whenever the amplifier outer top cover is removed, the High-Voltage transformer and the
cooling fan are unpowered. If tubes are installed in the amplifier during these tests, the user
should limit
On-Time
since cooling airflow will not be present. Read through the following
steps before actually performing them. If any problems are noted, switch the amplifier
OFF
,
then unplug from the AC mains.
1. Ensure the amplifier “POWER” switch is in the
OFF
position.
2. Plug the amplifier into the AC mains.
3. While observing the front of the amplifier, switch the amplifier
ON
.
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Summary of Contents for TL-922 Revival (tm)
Page 13: ...6 Figure 3 1 TL 922 Revival tm Upgrade Kit Contents www KesslerEngineeringLLC com...
Page 18: ...11 Figure 3 4 LED Circuit Board Correctly Installed www KesslerEngineeringLLC com...
Page 30: ...23 Figure 3 19 QSK PCB to QRO Output Connections www KesslerEngineeringLLC com...
Page 34: ...27 Figure 3 23 Electronic Bias PCB Installed www KesslerEngineeringLLC com...
Page 47: ...40 Figure 3 30 Step Start PCB www KesslerEngineeringLLC com...
Page 49: ...42 Figure 3 33 LED Schematic Diagram Figure 3 34 LED PCB www KesslerEngineeringLLC com...
Page 50: ...43 Figure 3 35 Electronic Bias Schematic Diagram www KesslerEngineeringLLC com...
Page 51: ...44 Figure 3 36 Electronic Bias PCB www KesslerEngineeringLLC com...
Page 54: ...47 User Notes www KesslerEngineeringLLC com...
Page 55: ...48 5 1 User Notes Continued www KesslerEngineeringLLC com...
Page 56: ...49 5 2 User Notes Continued www KesslerEngineeringLLC com...
Page 57: ...50 5 3 User Notes Continued www KesslerEngineeringLLC com...
