User Guide

Technical Documentation
NHB–3
PAMS
Troubleshooting
Original 26/97
Page 4
Third Mixer 23
Third IF–filter Z551 23
Third If amplifier 24
RX Signal levels and frequencies 24
Setting of PCLocals 24
Signal Levels at Front End 24
Signal Levels at IF (1) 24
Signal Levels at IF (2) 25
Signal Levels at IF (3) 25
TX Unit 26
Modulator circuit,TX–part of CRFRT ( N551 ) 26
Upconversion mixer ( V702 ) 26
TX interstage filters ( Z713 and Z727 ) 26
1st TX–buffer ( V710 ) 26
2nd TX–buffer ( V725 ) 27
3rd TX–buffer ( V736 ) 27
Power amplifier 27
Power control circuitry 27
TX signal levels and frequencies 28
Settings of PCLocals 28
Signal levels of UHF VCO buffer ( V701 ) 28
Signal levels of 1st amplifier 28
Signal levels of 2nd amplifier 28
Signal levels of 3rd amplifier 29
Signal levels of power amplifier 29
Synthesizer 30
Brief describtion of the synthesizer 30
Reference oscillator 30
UHF–part of PLL 30
VHF–part of PLL 30
Synthesizer Signal levels and frequencies 31
UHF Synthesizer Malfunction 31
Setting of PCLocals 31
Synthesizer locked ( Control voltage depends on channel) 31
Voltages of synthesizer N820 : 31
UHF VCO (G1) output: 31
Reference oscillator VCTCXO 32
VHF Synthesizer Malfunction 32
Voltage from Do IF 32
Voltages of N820 32
Biasing voltages on VHF 32