User Manual

AMPLIFIER CONTROLLER BOARD REV.5
PUB12-030 Rev. 1 Feb 14, 2013 12-030-25 Amplifier Controller Board Rev.5
The gain of the amplifier stage at U14D can be adjusted by selecting one of the three available feedback resistors
R79 (6.2K ohms) or R82 (24K ohms) or R148 (20K ohms) using jumper E14. When the lowest gain is desired, E14
is placed in the LO position selecting R79 in parallel with R148. When the middle gain is desired, E14 is placed in
the MID position selecting R82 in parallel with R148. When the highest gain is desired, E14 is not installed leaving
only R148 in the feedback path.
Outputs from unity gain op-amps U14A, U14B and U14D drive the reflected power metering circuits. The output of
U14A provides telemetry to the CPU A/D converter input. The output of U14B provides telemetry to the CUTBACK
and VSWR circuitry. The output of U14C provides telemetry to the remote controls. Bench test calibration consists of
adjusting R72 with rated, properly modulated input while observing the voltage at TP5, which should read 4.0 volts
DC for full scale calibration.