Icom IC-746 - Section 4: Circuit Description; RF Switching Circuits; RF Filter Circuit (RF Unit); Receiver Section Circuitry

IC-746 FAQ
LCD Driver Transistor Replacement.................................................................... 84
Poor Man's TCXO ................................................................................................ 85
Upgrading Stock Ceramic IF Filter to a Crystal Filter ......................................... 85
7.3 Can I increase my RF power output beyond 100w?........................................ 85
7.4 I'm brave; what untested "mods" are there?................................................... 86
Replacing PIN Diodes in the Demodulator .......................................................... 86
Removing the BCB Attenuator............................................................................. 87
7.5 What "external" mods are there for the IC-746?............................................ 87
Remote, Direct Frequency Entry Keypad............................................................. 87
Cordless Headset Microphone .............................................................................. 87
Automatic Antenna/Amplifier Selection by Band................................................ 87
2m TX/RX Sequencer........................................................................................... 88
External Tuner Pulser ........................................................................................... 88
Unmuffling Icom Hand Mics................................................................................ 89
8 MISC........................................................................................................ 90
8.1 Are there different versions of the IC-746?...................................................... 90
8.2 Can I operate 2m on reduced power?............................................................... 90
8.3 Where can I find plugs for the ACC connectors?............................................ 90
8.4 What are the pin-outs on the ACC-1 connector?............................................. 91
8.5 What are the pin-outs on the ACC-2 connector?............................................. 92
8.6 Does audio to pin 4 of ACC-1 trigger the VOX?.............................................. 92
8.7 Where can I get replacement power connectors? ............................................ 92
8.8 Where can I get replacement microphone connectors? .................................. 93
8.9 What is "Lo-Fi" SSB operation?....................................................................... 93
8.10 What is "Hi-Fi" SSB operation? ....................................................................... 93
8.11 How does one improve the fidelity of a received signal?................................. 94
8.12 How does one improve transmission fidelity?.................................................. 95
8.13 Can the IC-746 transmit at less than 5 watts? ................................................. 95
8.14 How do I turn on both HF pre-amps at the same time?.................................. 95
8.15 How do I adjust the 746 for best AM performance? ....................................... 96
8.16 Is the IC-746 suitable for CAP and MARS operation? ................................... 96
8.17 How do I adjust the Noise Reduction (NR)? .................................................... 96
8.18 How do I program a non-standard repeater offset?........................................ 97
8.19 How do I turn on repeater (PL) tones?............................................................. 97
8.20 How do “zero-beat” a CW signal? .................................................................... 98
INSTRUCTION MANUAL ERRATA ............................................................................. 99
Page:2 Incorrect Page References.................................................................................. 99
Page:6 External speaker and remote interface jacks are swapped. ........................... 99
Page:9 Incorrect page references................................................................................... 99
Page:15 BAND EDGE BEEPS simply do not work as expected................................... 99
Page:19 SSB TX Tone affects more than SSB ................................................................ 99
Page:22 TRANSMIT button does not transmit on CW................................................. 99
Page:27 Only one bar for CW sidetone level, not two.................................................. 100
Page:32 No ALC adjustment for FM............................................................................. 100
Page:33 Incorrect filter diagram.................................................................................... 100
Page 7 of 113
2003-02-08