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RESET
The HLV-350 operation is internally monitored by many highly efficient protection circuits.
If any limit is exceeded the device shuts off. If any protection circuit is activated the red
"PROTECTION"-LED illuminates as well as one of the three protection circuit LEDs
"ANTENNA", "OVERDRIVE" or "TEMPERATURE". At the same time, an acoustic
signal sounds. The internal beeper can be switched off when not needed. Access to the micro
th
switch is through the 17
air gap in base plate in the near of the Standby switch. An alarm
signal of 5V DC is fed to Pin 1 of the "CONTROL"-jack for any monitoring purpose. To
turn the amplifier on again the "RESET"-switch must be turned off for a short time and then
on again.
Attention:
Please insure that the amplifier is disconnected from the mains when disabling
the audible alarm.
7. Protection circuits
The HLV-350's internal control circuit supervises the output load condition, any
overdrive of the input stage and the thermal status of heat sink and power supply
unit. If the amount of reflected power exceeds 100 watts, the protection circuit
shuts off the RF unit immediately and switches the drive power to bypass mode.
This also happens with overdrive levels of more than 15% of the rated value or
when overheating the amplifier by >55°C or 130°F.
CAUTION
Although the internal protection circuits are very efficient they cannot
assure a 100% safety. Especially short pulses at the input due to delayed
ALC performance of >75W transceivers used with up to 5dB over swing
can damage the power transistor. Direct radiation due to a too small
distance between the antenna and the amplifier can cause feedback effects
or misleading the threshold levels of the protection circuits.
9
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