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7. Protection and Treatment for Shutdown
The HL-450B is equipped with the following six protection functions, and the LED of
"PROT" lights when an abnormality is detected.
(1) Over-Voltage
The LED of "PROT" lights when the power supply voltage exceeds 16 V.
Check the DC power voltage.
(2) Antenna SWR
The LED of "PROT" lights when the matching condition of the antenna is poor and the
SWR exceeds 2.
Check the maximum power handling capacity of the antenna, and lower the SWR
accordingly.
(3) Over-Drive
The LED of "PROT" lights when the RF drive from the radio exceeds 50 W.
Adjust the drive level of the radio not to exceed 50 W.
Make the ALC connection, if needed.
(4) Band Mis-Set
The LED of "PROT" lights when the amplifier is driven by a higher frequency signal than
the selected frequency band in manual mode.
Correct the band selection.
(5) Over-Current
The LED of "PROT" lights when DC current of 65 A or more flows into the amplifier.
DC current flow varies depending on SWR condition of the antenna.
Correct the matching or reduce the drive power.
(6) Over-Temperature
The LED of "PROT" lights when the internal temperature reaches 70°C.
Leave it in the standby state (receiving) for a while until the temperature falls.
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