Larcan Inc MXI1503U Manual Do Utilizador
MXI1503-2004 OPERATIONS AND MAINTENANCE
PUB13-10 Rev 1
10
6
TEST AND TROUBLESHOOTING
6.1 B
ENCH
T
EST
P
ROCEDURES
The following procedures are test instructions for the amplifier modules comprising the MXi amplifier.
6.1.1 Front-End Module, 21B2860G7, Bench Test Procedure
Connect +32V to TP2. Limit the power supply current 1A. Check that the current consumption is about
0.30A.
0.30A.
Apply a 0dBm (1mW) RF input to the amplifier.
Turn RV2 fully clockwise. The Front-End module should have a gain of about 14dB. Adjusting RV2 from
one extreme to the other should vary the gain by 25dB. Set RV2 fully clockwise after checking the range
(maximum Gain)
one extreme to the other should vary the gain by 25dB. Set RV2 fully clockwise after checking the range
(maximum Gain)
Set phasing adjustment, RV1, fully clockwise (Phasing not required in this model).
RF Mute Check: Connect a variable power supply to TP1. Gradually increase the voltage until the gain
drops by 20dB or more. The applied voltage should be about 7.0 volts in this condition.
drops by 20dB or more. The applied voltage should be about 7.0 volts in this condition.
Telemetry (not used on all models): Monitor TP3. Note that the voltage on TP3 decreases to 0.0V when
RF output has been muted.
RF output has been muted.
6.1.2 Driver Pallet, 21B2708G3, Bench Test Procedure
BIAS SETTING: Connect a 50-Ohm load to the output of the Driver pallet.
Before applying +50V to the module, adjust R11 fully counter-clockwise (CCW). Limit the power supply
current to 1.0A.
current to 1.0A.
Apply +50V to the B+ terminal. Monitor the Drain current and adjust R11 clockwise (CW) for a current of
0.35A + 0.05A.
0.35A + 0.05A.
Proceed to the next step if a network analyzer or similar equipment is available.
RF SWEEP: Check that the gain of the Driver pallet, in the frequency range of 470MHz to 806 MHz. is
between 20 to 22dB.
between 20 to 22dB.
6.1.3 PA Pallet 21B2729G1 Bench Test Procedure
BIAS SETTING: Connect a 50-Ohm load to the output of the PA pallet.
Before applying +50V to the module, adjust R11 fully counter-clockwise (CCW). Limit the power supply
current to 2.0A.
current to 2.0A.
Apply +50V to the B+ terminal. Monitor the Drain current and adjust R11 clockwise (CW) for a current of
1.45A + 0.05A.
1.45A + 0.05A.
Proceed to the next step if a network analyzer or similar equipment is available
RF SWEEP: Check that the Gain of the PA pallet, in the frequency range of 470MHz to 806MHz, is between
20 to 22 dB.
20 to 22 dB.
6.1.4 Amplifier AGC Setup
Start With Amplifier OFF
Remove the AGC jumper, E16, from the control board to disable the AGC