Icom M700 Mods Updated

Unlocking the Potential: Essential Icom M700 Mods for the Marine and Amateur Radio Enthusiast

The Icom M700 is a legend. Built like a tank for the harsh marine environment, this 150-watt HF SSB transceiver was a staple on commercial vessels and cruising yachts for decades. While its rugged build and powerful output are still revered, the stock unit is showing its age—especially for amateur radio operators (hams) who acquire surplus units.

The IC-M700's native 48-channel limit is a significant bottleneck for modern amateur use. SRAM Expansion icom m700 mods

11. When to consult a pro or replace the unit

The first was a classic: the narrow CW filter. Eli found a NOS Murata ceramic filter on eBay, a tiny, fragile thing that cost more than the radio. Installing it meant decoupling the RF board with a special tool he had to 3D-print himself. His soldering iron, a fine-point Metcal, hovered like a hummingbird’s beak. One slip, and the whole board was a paperweight. He didn’t slip. The result was miraculous—a scalpel’s edge of selectivity. Signals emerged from the mush like clean bones from a fossil. Unlocking the Potential: Essential Icom M700 Mods for

• Mod: Change C239 (on the MAIN unit) from 0.047 µF to 0.01 µF. This raises the low-frequency roll-off.
• Result: Clearer, more intelligible SSB audio.

Before attempting any mods, consider the following: When to consult a pro or replace the unit

ICOM M-700 Modification Report