Icom M700 Mods Info

: Look for a row of small switching diodes (usually labeled in the component schematic near the microprocessor).

Standard M700 and M700TY models are typically frequency-locked to transmit only on marine bands, which often exclude amateur frequencies. The main goal of many modifications is to remove this restriction. A mod for the IC-M700D (German version) identifies that disabling a "Transmitter Mute" (TMU) circuit by removing or installing a jumper (W1037 on the logic board) can unlock full-band transmit capability. More generally, for the base IC-M700, amateur Gary Fiber suggests locating jumper W37 on the logic board and changing its state (if open, close it; if closed, open it) to unlock transmit on amateur frequencies.

: By clipping the line that senses the Push-To-Talk (PTT) switch on the Clarifier circuit and tying it to a constant 8V DC source inside the radio, the Clarifier will remain active during transmission. This allows you to "net" perfectly onto an amateur radio frequency. 3. Microphone Audio & Compression Upgrades icom m700 mods

: Replacing the varactor diode or modifying the resistor network feeding the Clarifier potentiometer allows for a wider Receiver Incremental Tuning (RIT) swing of up to

These modifications require precise soldering skills and basic knowledge of electronics. Proceed at your own risk. 🔓 1. General Coverage Transmit Mod (Frequency Expansion) : Look for a row of small switching

Quick checklist for a safe mod/install

A word of caution: the M700 was not designed for the continuous full-power operation that Pactor modems often demand. Furthermore, it lacks a dedicated TNC interface necessary for seamless connection to Pactor modems. The radio is only capable of approximately 50 watts continuous output, making it less than ideal for demanding digital mode applications. For lighter digital modes such as PSK31, the M700 is considerably better suited. A mod for the IC-M700D (German version) identifies

The Icom IC-M700 is a classic piece of marine HF (High Frequency) hardware. Known for its rugged construction and powerful 150-watt transmitter, it was a staple in maritime communication for decades. Today, many of these units have found their way into the hands of amateur radio operators and collectors who seek to adapt the radio for non-marine use. The Appeal of the IC-M700

After cutting the diode lead, ensure the cut ends do not touch. Power on the radio and attempt to tune to a standard amateur radio frequency (like the 40-meter or 20-meter band) to verify that the transmit indicator engages. 2. Audio Quality and Filter Upgrades

The detailed above—especially the PLL unlock and the audio tap—turn a clunky marine brick into a serious contesting, DX, and digital mode machine. It's heavy, it's loud, and it's nearly indestructible.