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EUROTEL - ITALY
ETL0480TBD
II - OPERATING PROCEDURES
1 ) First time operation of ETL0480TBD
•
Locate the three switches on the front panel of the A.C. Mains Distribution module, near the bottom
of the cabinet. Switch on the mains switch to distribute mains to the cabinet, the three red lamps on
the front panel should turn on, switch on the RF Amplifiers, switch on the Exciter, noise from the fan
should be heard.
•
Check that the Multi-function Metering Display is configured as follows.
•
Amplifier N°1:
⇒
FINAL F/R (upper row): shows the total
RF FORWARD
output power.
⇒
FWD peak (lower row): shows the total RF FORWARD output of
this Amplifier
.
•
Amplifier N°2:
⇒
FINAL F/R (upper row): shows the total
RF REFLECTED
output power.
⇒
FWD peak (lower row): shows the total RF FORWARD output of
this Amplifier
.
The following procedure must be followed to make sure that the RF cable connections are properly
done:
⇒
Decrease the output power of the exciter by fully rotating counter clock wise the multi-turn
potentiometer (about 15 turns) labelled “Power” on the front panel of the A.G.C. – A.L.C.
Controller plug-in module.
⇒
Turn on the exciter with video modulation signal applied.
⇒
Increase the exciter output power by clock wise rotating the multi-turn potentiometer
labelled “Power” on the front panel of the A.G.C. – A.L.C. Controller plug in module until
reaching about 100W output power on each one of the amplifier modules.
⇒
Check simultaneously that the total forward output power level “”
is about 200W and the total reflected power “FINAL F/R on Amplifier 2” is about 0W.
⇒
If the above values are correct slowly increase the power until reaching 1000W of total
output power, and readjust till reading on Amplifier N.1 an A.L.C. value comprised
between
-5.0% end +5.0% (The A.L.C. control is done on Amplifier N.1).
•
If the output RF power is too low to allow control (in this case the green LED “ON AIR” will be off),
the A.L.C. will not start the control.
•
The A.L.C. is always best positioned at mid range. To align the A.L.C. voltage
, wait at least for half an
hour at full power, to allow the system to reach thermal equilibrium
and then locate the “POWER”
screwdriver control on the front panel of the Exciter (A.G.C.-A.L.C. CONTROLLER plug-in). Insert a
small screwdriver and slowly adjust, while looking at the Multi-function Display on the Amplifier 1:
the optimum value is around 0.0%.
•
Remove the vision signal from the Exciter and check that the RF output power drops to 50% or
lower reading. In this condition the LED ON AIR will turn off.
October 2002
CMAN0480ENG
Page 23