MANUALE INGLESE AMPLIFICATORE HVLA700AY REV.0
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ON THE ALC REGULATION “ALC LEVEL ADJ”
On the back of the amplifier you find a knob labeled “ALC LEVEL ADJ” (in succession called knob) which serve
for dosing the negative ALC voltage that has to be sent to the HF transceiver; seen that a specific voltage does
not exist, we recommend to operate in the following way:
NOTE:
transceiver initial settings = BAND: 20m - MODE: RTTY - PWR OUT: 50 watts
1) Rotate completely the knob counter-clockwise (as by factory).
2) Insert a good “Wattmeter” instrument at the output of the amplifier, make operative the amplifier with a
drive power of 50 watts and take note of the output power.
NOTE:
we recommend to use a 50 ohms dummy load at the output of the amplifier; in alternative, the antenna
must present a VSWR value as lower as possible (ideal 1.1:1).
3) Set in “stand-by” the amplifier.
4) Set the output power of the transceiver at 60 watts.
5) Make operative the amplifier and regulate the knob clockwise until you read on the Wattmeter a output
power corresponding this one to a drive power of 50 watts ; now adjust still the knob counter-clockwise
(+/- 20 degrees) and stop here.
6) Set in “stand-by” the amplifier.
7) Set the drive power of the amplifier, by emission mode, to the desired value.
The regulation is done and now you can remove the Wattmeter.
NOTE:
The yellow LED labeled “ALC” placed on the front show the ALC working.
ON THE PROTECTION “ALARM”
When:
a) the frontal switch labeled “FILTER” is placed in a wrong working band;
b) the antenna system shows a high VSWR value (more than 2:1), open antenna or short circuit antenna;
c) the input drive power is more.
the protection will immediately intervene signaling, with the lighting of the red LED labeled “ALARM” placed on
the frontal, the happened anomaly.
After having verified and solved the cause, operate on the frontal switch labeled “STBY/OP”, to restore the
normal operation of the amplifier.
NOTE:
in case of alert due to an excess of drive power you have to switch OFF the amplifier with the switch
placed on the back, wait a few seconds and then switch ON the amplifier.
ON THE PROTECTION “OVER TEMP”
When:
a) the duty cycle and/or the operative mode of the amplifier is particularly intense and/or heavy;
b) the drive power is excessive;
c) you do not use the ALC circuit;
d) the antenna system has a high VSWR but no able to make intervene the protection;
e) the enviromental temperature, in which the amplifier works, is particularly high;
f) the air apertures are, in some ways, obstructed;
g) the amplifier has not abundant air circulation in all the sides;
h) there is a damage in forced air cooling system;
the protection will immediately intervene signaling, with the lighting of the red LED labeled “OVER TEMP”
placed on the frontal and the contemporary switch OFF of the green LED labeled “OP” placed on the frontal, the
happened anomaly putting the amplifier in the “stand-by” position.
When the temperature reaches its normal values, the amplifier will automatically return in operation.
