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5_._Maintenance ... 5 5.1 Electrical Maintenance ... 5 5.2 Mechanical Maintenance ... 5 5-3 Storage ... 5 6._Performance Test ... 6 6.1 Preliminary Remarks ... 6 6.2 Required Measuring Equipment and Accessories ... 7 6.3 Checking the Puses PI and F2 ... 8 6.3.1 Changing the Puses FI and F2 ... 8 6.4 Battery Check ... 8 6.5 Illumination ... 8 6.6 Checking Operation by means of the Keypad . . 9 6.7 Tuning Knob ... 9 6.8 Function of Carrier Squelch ... 9 6.9 Checking the IF Filter ... 9 6.10 Frequency Accuracy ... 10 6.11 Checking the Signal Level Display and the Level Tone ... 11 6.12 Sensitivity ... 11 6.14 IP Rejection ... 12 6.16 Checking the AFC Function ... 13 6.17 AF Output ... 13 6.18 AF S/N Ratio at Vln = 1 mV . .' ... 13 6.19 Checking the Power-Down Logic for the CPU D301 ... 13 6.20 Peak rectifier ... 14 t 6.21 IF Output ... 14 _Troubleshooting of Subassembly ... 15 8_._Removal of Subassemblies ... 18 8.1 Synthesizer ... 19 8.2 Tuning Unit ... 19 8.3 Tuner ... 19 8.4 IP Section ... 20 8.5 Control Unit ... 20 9 ._Circuit Description ... 21 9.1 Tuner ... 21 9.2 IP Section ... 22 9.3 Synthesizer ... 25 9.4 Control Unit ... 25 9.5 Tuning Unit ... 28 10._Troubleshooting and Repair of Subassemblies ... ... 31 10.1 Preliminary Remarks ... 31 10.1.1 Spare Parts ... 31 10.1.2 Required Measuring Equipment and Accessories ... 32 10.2 Troubleshooting ... 35 10.2.1 Tuner Fault Tracing Chart ... 35 10.2.2 IF Section Fault Tracing Chart ... 39 10.2.3 Synthesizer Fault Tracing Chart ... 43 10.2.4 Control Unit Fault Tracing Chart ... 46 10.2.5 Tuning Unit Fault Tracing Chart ... 52 10.3 Electrical Test and Adjustment of Subassemblies ... 54 10.3.1 Tuner ... 54 10.3.1.1 Checking the Overall Gain ... 54 10.3.1.2 Checking the 40-dB Attenuator . ... 55 10.3.1.3 Checking the 1st VHF/UHF Amplifier and 1000-MHz Lowpass Filter ... 55 10.3.1.4 Checking 1st Mixer ... 55 10.3.1.5 Checking 2nd VHF/UHF Amplifier ... 56 10.3.1.6 Checking the Input Signal Path for f ^ 500 MHz ... 56 10.3.1.7 Checking the UHP Amplifier ... 57 10.3.1.8 Checking the Input Signal Path for f < 500 MHz ••••••••••••••••• 57 10 .3 .1*9 Checking 2nd Mixer and Subsequent Amplifier ... 58 10.3.1.10 Adjustment of the 650-MHz Lowpass Filter . . 58 10.3.1.11 Adjustment of the 629 .3-MHz Bandpass Filter ... 59 10.3.2 IF Section ... 60 10.3.2.1 Overall Check of IF Section ... 60 10.3.2.2 Checking the 128-MHz Oscillator ... 6l 10.3.2.3 Checking th Signal Path ... 62 10.3.2.5 Checking the Oscillator Reference Signals . . 63 10.3.3 Synthesizer ... 64 10.3.3.1 Checking the Oscillator Signal ... 64 10.3.3.2 Checking the Oscillator and the 512-MHz Mixer ... 64 10.3.3.3 Checking the Divider Chain ... 65 10.3.3.4 Checking the Reference Frequency Generation ... 65 10.3.4 Control Unit ... 65 10.3.4.1 Checking the System Clock ... 66 10.3.4.2 Checking the Reading and Writing Signals . . 66 10 *3 *5 Tuning Unit ... 66 10.3.5.1 Checking the Tuning Pulse Generation ... 66 10.3.5.2 Checking the AF Amplifier ... 66 10.3.5.3 Checking the Level Tone Generator ... 67 Pig. 11-1 Test set-up for functional test Pig. 11-2 Test set-up for checking the 3-db bandwidth 150 kHz Pig. 11-3 Test set-up for checking the peak rectifier Pig. 11-4 Removal of assemblies (without control unit) Pig. 11-5 Removal of Control Unit Service documentation