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DOCNUMBER 8410
Document Issue 1.1
August 2015
Page 7–5
RKR Designs LLC
Alpha 8410 Linear Amplifier User Manual
Diagnosing Faults and Troubleshooting
Amplifier turns on but HV
reading is low as indicated on
the multimeter bargraph
The plate voltage to the power supply may be too low. Check the line
voltage and confirm that the tap is set correctly.
Amplifier turns on but time
delay does not complete and
WAIT LED does not turn off
The timing circuitry on the control board may be damaged or defective.
Contact RKR Designs technical support.
Amplifier turns on and time
delay completes but amplifier
does not transmit
The T/R control-line (key-line) connection to the amplifier may be faulty.
1. Confirm that the key line is inserted into the correct jack on the back
of the amplifier.
2. Confirm that the key line is connected to the correct port on the
transceiver and that amplifier-keying is enabled.
3. If the tube current has exceeded 2.5 A, follow the resolution
instructions for
“Fault type 2,” page 7–2
and
“Fault type 5,”
page 7–3
.
4. Confirm that the cable is good.
5. Confirm, with the multimeter switch in the Ip position and the
amplifier keyed with no RF, that plate current is drawn.
Amplifier operates properly,
then turns off completely
The tube current may exceed ~2.5 A. See the resolution instructions for
“Fault type 4,” page 7–3
.
Amplifier transmits but red
GRID LED lights often
The amplifier may be overdriven or incorrectly tuned; most likely the load
control is set too low. Reduce the transceiver output and adjust the tune
and load controls to maximize efficiency with minimum grid lights.
When switching from STBY to
OPR mode, receive signals
disappear or are severely
attenuated
1. The RELAY (T/R) control cable from the transceiver may be shorted.
Check the cable to ensure that it is switching properly. Replace it if
needed.
