Preference

The intent of this article is to help the semi-non-technical person understand what is inside the Drake TR-7(A) Transceiver, how it works, and discusses simple adjustment and modifications the end-user can perform.    I start with a basic overview of the inside of the radio and how the signals flow.    I show each plug-in circuit board with a brief description of its function or purpose.   Towards the end of the article I go through several simple alignment procedures, discuss a few simple radio modifications to enhance the operation, and troubleshooting information.   The last four pages is the Drake TR-7 color brochure published during the production of the radio.

• Brief Introduction and History behind the TR-7
• TR-7 Board Layout
• The Parent Board

Page 2

• The Road Map 
• How Signal Flow Through The Radio

Page 3

• The Power Cable
• Wiring A Microphone
• The Rear Panel Accessory Connectors

Page 4

• The Up-Converter Board
• The VCO Board
• The Translator Board
• The PTO Assembly

Page 5

• The 2nd Mixer Board
• The IF Switching Board
• The Noise Blanker Accessory Board
• The IF Filter Board

Page 6

• The Pass Band Tuning Board
• The IF/Audio Board
• The Transmit Exciter Board

Page 7

• The Digital Board
• The AUX-7 Accessory Board
• The Digital Display Board
• The Power Supply Board

• The Power Amplifier
• The High Pass Filter boards
• The Low Pass Filter Boards
• The ALC Board

Page 9 

• Making Basic Adjustments To The TR-7
• The Power Meter Calibration
• The RIT Centering Adjustment
• The Radio Mode Frequency Adjustments
• S-Meter, IF Gain, & CW Mode Off-Set Adjustments
• The ALC Adjustment
• The Transmit Carrier Balance Adjustment

Page 10

• The "Poor Man's" AM Filter Modification
• The All-Band Transmit Modification
• The TR-7 Quiet Fan Modification

Page 11

• The TR-7 Pin Diode Dilemma
• The High Pass Filter Board - Pin Diodes
• Troubleshooting Pin Diode Problems

Page 12

• Replacing The Internal Fuse
• Replacing The Dial Bulb Lamps
• Companion Articles
• Useful Function For The "Store" Switch
• Identifying The TR-7 Differences And Versions
• Transmit AM Mode Filter Modification
• Restoring the TR-7 Amplifier To Full Power

Page 13  -  The TR-7 Full Color Brochure - Front Page

Page 14  -  Brochure Inside Front Page

Page 15  -  Brochure Inside Rear Page

Page 16  -  Brochure Rear Page