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Valve Radio and Audio Repair Handbook, 2nd Edition

Book Description

This book is not only an essential read for every professional working with antique radio and gramophone equipment, but also dealers, collectors and valve technology enthusiasts the world over.

Table of Contents

  1. Cover image
  2. Title page
  3. Table of Contents
  4. Copyright page
  5. Dedication
  6. Preface
    1. Essential facts and figures
    2. Vintage radio, vintage terms
    3. The spares position
    4. Thanks
  7. Part 1
    1. Chapter 1: Basic facts you need to know about electricity and magnetism
      1. Electricity from batteries
      2. Electricity and magnetism
      3. Induction and transformers
      4. Practical transformers
      5. Auto-transformers
      6. Transformers and DC
      7. To sum up
    2. Chapter 2: What you need to know about voltage, current, resistance and Ohm’s law
    3. Chapter 3: What you need to know about real life resistors
      1. Standard values
      2. Resistors in series and parallel
      3. Series/parallel resistors and wattage
      4. What do resistors do in radio sets?
      5. Variable resistors
    4. Chapter 4: What you need to know about condensers
      1. Electrolytic condensers
      2. Leakage current and re-forming
      3. Condensers and AC voltages
      4. Variable condensers
      5. Pre-set condensers
      6. Yes, but what do condensers <span xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" class="italic">do</span>??
    5. Chapter 5: What you need to know about tuning
      1. A use for the acceptor circuit
      2. Frame aerials
      3. Air cores and iron dust cores
      4. Permeability tuning
      5. Ferrite rods
    6. Chapter 6: What you need to know about valves (1)
      1. Valve characteristics
    7. Chapter 7: What you need to know about valves (2)
      1. The triode as oscillator
    8. Chapter 8: What you need to know about the principles of transmission and reception
      1. Sidebands
      2. Receiver principles
    9. Chapter 9: Practical receiver design (1): battery operated TRFs
      1. Sharp cut-off versus variable mu
      2. Extending the tuning range
      3. Improving the output
      4. Automatic Grid Bias
    10. Chapter 10: Mains valves and power supplies
      1. Cathode bias
      2. Types of mains valves
      3. Negative smoothing
      4. ‘Swinging choke’ smoothing
      5. Directly or indirectly heated?
      6. The voltage doubler
      7. Isolated chassis
      8. Different mains supplies
      9. AC/DC receivers
      10. Barretters
      11. Rectifiers in AC/DC receivers
      12. ‘Live’ chassis
      13. Part AC-only sets
      14. Appendix
    11. Chapter 11: What you need to know about the superhet
      1. Keeping the local oscillator in step
      2. Automatic volume control
      3. An alternative delay method
      4. The ‘short’ superhet
      5. A good basis for study
      6. Reflex amplifiers
      7. Part superhets
      8. Battery superhets
      9. Appendix
    12. Chapter 12: Some more special features found in superhets
      1. Tuning indicators
      2. Automatic tuning
      3. Motor tuning
      4. Automatic frequency control
      5. Silence between stations
      6. Amplified AVC
      7. Push-pull output
      8. Better tone control systems
      9. Band-spread short wave tuning
      10. The double superhet
      11. ‘Television sound’
    13. Chapter 13: Battery and mains/battery portable receivers
      1. ‘All-dry’ portables
      2. Miniature valves
    14. Chapter 14: Automobile receivers
      1. Negative or positive earthing
      2. Constructional aspects
      3. Permeability tuning
      4. Some unusual sets and features
      5. AM/FM automobile receivers
    15. Chapter 15: Frequency modulation
      1. Some aspects of FM receiver design
      2. De-emphasis
      3. Design aspects of British FM receivers
  8. Part 2
    1. Chapter 16: Tools for servicing radio receivers
      1. Solder ‘guns’
      2. Solder
      3. What about instruments?
      4. What ranges are required?
      5. The ohms-per-volt game
      6. What does ohms-per-volt mean in practice?
      7. The right way round for meters
      8. The signal generator
      9. The resistance and capacity bridge
      10. What about an oscilloscope?
      11. The output meter
      12. Valve testers
      13. The Mullard ‘high speed’ valve tester
    2. Chapter 17: A few words about safety precautions
      1. The danger points
      2. Resistive mains cords
      3. More than two leads
      4. Spare conductors
      5. Nothing certain yet
      6. The safety routine
      7. Don’t relax your guard
      8. Genuinely AC-only receivers
      9. The isolating transformer danger
      10. Other hazards
      11. Fumes from solder
      12. Chemical warfare
      13. On your own
    3. Chapter 18: A logical approach to fault finding
      1. Initial tests
      2. Look for previous work!
    4. Chapter 19: Repairing power supply stages
      1. AC-only receivers
      2. Use the correct replacements
      3. Negative HT smoothing
      4. Low voltage negative bias
      5. RF by-pass and other HT decoupling condensers
      6. AC/DC receivers
      7. When the mains dropper fails
      8. Part AC-only sets
      9. Resistive mains cords
      10. Extra precautions necessary with AC/DC and part AC sets
      11. Barretters
      12. ‘Watt-less’ droppers
      13. Replacing ‘metal’ HT rectifiers
      14. Dealing with energised loudspeakers
    5. Chapter 20: Finding faults on output stages
      1. Replacing output transformers
      2. Watch out for negative feedback
      3. Transformers with three windings
      4. Some causes of low or distorted reproduction
      5. What about the output valve?
      6. Heater-to-cathode leaks
      7. Push-pull output
      8. Hot valves
      9. ‘Crackly’ tone controls
    6. Chapter 21: Faults on detector/AVC/AF amplifier stages
      1. General AVC problems
      2. Detection and AVC in ‘short’ superheats
      3. Indirectly heated double-diodes in battery receivers
      4. Grid leak and anode bend detectors
      5. ‘Westector’ diodes
    7. Chapter 22: Finding faults on IF amplifiers
      1. Deathly silence
      2. Another source of self-oscillation
      3. Beware
      4. Repairing faulty or damaged IF transformers
      5. Realignment with a signal generator
      6. ‘Staggered’ IFTs
      7. Aligning with a wobbulator and oscilloscope
      8. Alternative IFs
      9. Beware of HT!
    8. Chapter 23: Faults on frequency-changer circuits
      1. A case in point
      2. Faults on the aerial coils
      3. When realignment is necessary
      4. Optical bandspread
      5. RF amplifiers
      6. Rejectors
      7. Image rejectors
      8. Adjusting ferrite aerials
      9. Faults on the tuning condenser
      10. Tackling broken dial drive systems
      11. Some common types of dial drive
      12. Permeability tuning
      13. Dial pointers
    9. Chapter 24: Repairing American ‘midget’ receivers
      1. Tackling faults on resistive line cords
      2. Extra precautions necessary with midget sets
      3. Types of midgets
      4. Rectifiers and HT smoothing
      5. No decoupling required
      6. Output stages
      7. Detectors in TRF midgets
      8. RF amplifiers in TRF midgets
      9. Detector/AF amplifiers in superhet midgets
      10. IF amplifiers
      11. Frequency changers
      12. RF amplifiers in superhets
      13. Aerials
    10. Chapter 25: Repairing faults on automobile radios
      1. Realigning automobile receivers
      2. Can the polarity be changed?
    11. Chapter 26: Repairing battery operated receivers
      1. Conventional domestic and portable types
      2. Fault finding
      3. ‘All-dry’ and mains-battery sets
    12. Chapter 27: Oddities
      1. Replacing the output valve
      2. The Ekco BV67 (Figure 27.2)
      3. The Philips V7A
      4. The ‘monoknob’ receivers
      5. Philips and Mullard pushbutton receivers
      6. The wartime civilian receiver
      7. Meeting the specifications
      8. Valves and secrecy
      9. An opportunity missed
      10. The design of the prototype in detail
      11. The AVC system
      12. The battery version
      13. Breaking the mould
      14. Likely problems in servicing
    13. Chapter 28: Repairing FM and AM/FM receivers
      1. Realigning FM and AM/FM receivers
    14. Chapter 29: Public address and high fidelity amplifiers
      1. Design features
      2. Output powers
      3. The Osram PX4 push-pull amplifier (Figure 29.1)
      4. The Osram PX25 (Class A) amplifier (Figure 29.2)
      5. The Osram PX25 (Class AB1) amplifier
      6. The Williamson KT66 amplifier (Figure 29.3)
      7. Preamplifiers (Figure 29.4)
      8. Repairing amplifiers
      9. Faults on and around output valves
      10. Preceding stages
    15. Common abbreviations
      1. Ranges of frequencies commonly used in vintage radio
      2. Some obsolete radio terms which may be encountered in old literature
      3. Some colloquialisms used in vintage radio
  9. Part 3
    1. Appendix 1: Intermediate frequencies
    2. Appendix 2: Valve characteristics and base connections
      1. Order of presentation
      2. Interpreting receiving valve nomenclature
      3. ADDENDUM TO TABLE 17
    3. Appendix 3: How old is that radio set?
      1. Clues inside the set
    4. Index
    5. THE “POPULAR WIRELESS” Radio Handbook
      1. AN EVENTFUL RADIO YEAR
      2. B.B.C. RESIGNATIONS.
      3. MARCONI ROYALTIES.
      4. PORTABLE SETS.
      5. RAILROAD RADIO.
      6. NEW BROADCASTING STATIONS.
      7. A RADIO MUSEUM.
      8. SELECTED RADIO DEFINITIONS
      9. Aerial Interaction
      10. Aerials That Swing
      11. SELECTED “P.W.” CIRCUITS