The Vacuum Tube Shortwave Radio 2

COVER......Page 1
TITLE PAGE......Page 3
INTRODUCTION......Page 7
CONTENT......Page 9
The R.C.A. model 8Q2 Shortwave Radio......Page 15
Cleaning......Page 16
Tube Testing......Page 17
Moveable Parts to Lubricate......Page 18
Variable Capacitors......Page 19
Wafer switches, tone and volume controls......Page 20
Knobs......Page 23
Dial Cord......Page 24
Speaker Repair......Page 25
Vacuum Tubes......Page 27
Diode......Page 28
Electron-Ray Indicator Eye Tube......Page 29
Triode......Page 30
Triode Function......Page 31
Pentagrid Converter......Page 32
Class A Biasing......Page 33
Full-Wave Rectifier Power Supply......Page 37
Why full-wave rectification?......Page 38
Function of the Full-Wave Rectifier......Page 39
Filtration......Page 41
Locating Electronic Components......Page 44
Other Full-Wave Power Supplies......Page 46
Electrolytic Capacitor Polarity......Page 47
Electrolytic Capacitor Isolation......Page 50
Push-Pull Audio Output......Page 51
Audio Side A......Page 53
Component Function, Side A......Page 54
Feedback Circuit......Page 55
Audio Side B......Page 56
Component Function, Side B......Page 57
Tone Control......Page 58
Push-Pull Output Quality......Page 59
Phase Inverter......Page 61
Volume Control......Page 63
The Phase Inverter......Page 64
Component Function......Page 65
Component Function (continued)......Page 66
Transformer Phase Inverter......Page 68
Screen Grid Phase Inverter......Page 69
I.F./Detector AVC and Eye Tube......Page 71
I.F.......Page 74
Detector AVC......Page 76
Eye Tube......Page 77
Component Function......Page 78
Component Function (continued)......Page 79
Tuning Meter Indicator Circuit......Page 80
Local Oscillator Mixer Converter......Page 81
Switch S3 and S4......Page 83
The Oscillator......Page 84
Tuned Circuit......Page 85
Function of the Mixer Converter Circuit......Page 86
Component Function......Page 87
Radio Frequency Amplifier......Page 89
Antenna Tuning......Page 91
R.F. Amplifier and Output......Page 92
Component Function......Page 93
Continuity Testing Transformers, Coils and Resistors......Page 95
Test Points for the Power Transformer......Page 96
Test Points for the I.F. Transformers......Page 98
Test Points for the Antenna Coils......Page 99
Test Points for the R.F. Coils......Page 100
Test Points for the Oscillator Coils......Page 102
Test Points for the Speaker......Page 103
Testing Resistors......Page 104
Mica......Page 105
Wax Capacitors......Page 106
Electrolytic Capacitors......Page 107
Spare Parts......Page 109
I.F. Transformer replacement......Page 111
Power Transformer Replacement......Page 112
Coil Repair......Page 113
Tube Adapters and Re-Basing......Page 114
Safe Working Environment......Page 117
Isolation Transformer......Page 118
Variable Transformer......Page 119
Power Up Test......Page 120
Overview......Page 122
Alignment Test Points......Page 123
Signal Generator......Page 124
NOTE #3:......Page 125
NOTE #4:......Page 126
Alignment Procedure - 5......Page 127
TABLE 11 - 1 Alignment Procedures for the R.C.A. Model 8Q2 Radio......Page 128
Alignment II......Page 129
Step #4......Page 130
The Key and Purpose......Page 131
Where to Start?......Page 132
No Current......Page 133
C34, No B+......Page 134
B+ at C34, No Plate Voltage......Page 135
Remove Rectifier Tube......Page 136
Current is Now Low (rectifier tube is removed)......Page 137
Current is Still High (rectifier tube is removed)......Page 138
T1 Runs Hot, but steady......Page 139
T1 Runs Hot, and Increasing in Temperature......Page 140
Is T1 still running hot and increasing in temperature? NO......Page 141
Does The Radio Play On Any Band? Yes......Page 142
Does The Radio Play On Any Band? NO......Page 144
Is a 60-Cycle Hum Heard at the Speaker? Yes......Page 145
Signal Tracing......Page 146
Building a Signal-Tracer......Page 147
Where to Start Signal-Tracing......Page 148
Does the Signal-Tracer Detect Audio at the MID-POINT? Yes......Page 149
Does the Signal-Tracer Play at V2 pin 3? Yes......Page 150
Does the Signal-Tracer Play at V2 pin 3? NO......Page 151
Using an Oscilloscope......Page 152
Using a PLL Radio......Page 153
The 60-Cycle Hum......Page 154
Thunder Storm Noise......Page 155
TABLE 12 - 1 R.C.A. Model 8Q2 Radio Signal-Tracer Test Points......Page 156
NOTE:......Page 157
Troubleshooting the oscillator circuit......Page 158
Locating the fault in the circuit......Page 159
Fault located......Page 163
Repairing the Wafer Switch......Page 164
Re-installing the oscillator unit......Page 165
Removing and Replacing......Page 167
Troubleshooting Outline......Page 171
APPENDIX......Page 173
GLOSSARY......Page 189
INDEX......Page 199