Page 71 (Front End Board Alignment)

DRAKE R8 - Front End Board Alignment

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Table of Contents

Addendum2
Safety Instructions3
Safety Precaution3
Product Safety Notice3
Table of Contents4
Using the R8/R8E Service Manual6
Locating a Malfunction6
Generalized Theory of Operation7
Receiver Section7
Frequency Control8
Interconnect Drawing Parts List9
Mescellaneous Chassis Parts9
Receiver Block Diagram11
Interconnect Diagram12
Circuit Description13
Front End Board Theory of Operation13
Front End Board Parts List15
Front End Board Schematic19
Theory of Operation25
Noise Blanker25
Step Variable BPF25
IF AMP and AGC Generator25
Audio Processing26
-5 VDC Generator26
Second if Board Parts List27
2Nd If/Audio/Power Supply Board Schematic33
2Nd If/Audio/Power Supply Board Pictorial36
Synthesizer/Microprocessor Theory of Operation39
Reference Oscillator39
1St lo39
Inner Loop PLL339
Middle Loop PLL240
Outer Loop PLL141
2Nd LO/PBT42
Bfo/Digital Mixer42
VHF Reference42
Synthesizer and Microprocessor Board Parts List43
Synthesizer Block Diagram51
Synthesizer Circuits Schematic53
Synthesizer/Microprocessor Board Pictorial55
Digital Section - Theory of Operation57
Microprocessor and Memory57
Radio Controls57
Microprocessor Block Diagram59
Microprocessor Circuits Schematic60
Front & Rear I/O Theory of Operation61
Front Panel Board Parts List63
Keyboard Switch Matrix Diagram64
Keypad Schematic - PC Art64
8 Keypad Schematic PC Art64
Front Panel Board Schematic65
Front Panel Board Pictorial66
Alignment69
Power Supply Voltage Checks and Setting Clock/Timer69
Synthesizer and PBT Alignment and Test69
35 Mhz Reference Oscillator69
Loop 2 Adjustments70
Loop 1 Adjustments70
50 Khz BFO Checks70
Front End Board Alignment and Test71
Check of Front End Bandpass Filters71
Antenna Switching Checks71
45 Mhz if Section Alignment and Tests71
Image Reject Mixer Section Alignment and Tests72
FM Squelch Adjustment72
F.M. Detector Alignment and Checks72
Second I.f./Audio Board Tune up and Test73
50 Khz if Filter Tune up73
A.G.C. and S-Meter Setup73
SSB-AM Squelch Setup73
Recovered Audio Output Tests74
Notch Null Adjustments74
Synchronous Detector Setup74
Noise Blanker Check and Adjustment75
VHF Converter Accessory77
VHF Block Converter Theory of Operation79
RF Section79
Control79
Synthesize79
VHF Converter Board Schematic85
VHF Converter Board Pictorial86
VHF Converter Alignment87
VCO Test and Tune87
Preselector Tuning and Checks87
Low Band87
Sensitivity and Microphonics Test88
High Band88
High Band Filter Response88
Sensitivity Test88

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