Baking More Boards...

Update Jan 7, 2025: We ran out of stock! We will be receiving more boards in late February. In the mean time, you can pre-order today for a 20% discount. Thanks for the support!

About

This is a drop-in replacement control board (Connect Unit B-9128B) for the Icom IC-705 radio. Designed by Ben (KD9LJF), it is an easy upgrade for any IC-705 radio.

Installation Guide

We have a step-by-step picture installation guide on our website: https://ihelpu.tech/icom-705-usbcsend-install-guide

You can also find a video explanation and overview here: https://www.youtube.com/watch?v=H1DPDUeaDfw

USB-C

The upgraded control board has a USB-C port that retains all of the original port's functionality (including computer data). This port is just a connector swap and works identically to the original board. This means that it does not add any USB-C Power Delivery (PD) features. You can still charge the radio through the USB connector with any USB-C charger, but it will still only charge at 5V and around 7.5W from the charger with the radio turned off.

SEND line

The SEND/ALC circuit has also been upgraded for additional protection for connecting external amplifiers. The original board from Icom was only capable of switching less than 30mA of current on the SEND line. Connecting an amplifier that operates by switching 12V to ground would likely fry your original board as it did for mine. Our new control board has upgraded MOSFETs for the SEND line that can switch up to 1.0 amp of current. We also added a Zener diode to protect against voltage spikes above 16V. Our upgrade to this circuit makes your 705 compatible with most 12V amplifiers without additional adapters other than the TRS 3.5mm cable.

Known Amp Compatibility List

Help us build an amplifier compatibility list! Message us with the amp model you've tested with the upgraded board.

So far, we have tested the following amps:

• Homebrew 12V amp
  
• TenTec Titan Amp (Vacuum Relay)
• Xiegu XPA125B
• Elecraft KXPA100
• RM Italy HLA305 & MLA100

Please keep in mind that most amplifiers will work even if they are not directly listed on the compatibility list.

Warning against powered buffers

Powered buffers for the SEND line, such as the Ameritron ARB-702i, are known to damage both the stock control board and this replacement upgrade board. I advise against using them with this upgrade board and recommend connecting the amplifier directly to the control board.

Warranty

The USB-C Control Board has a one-year warranty. (Warranty does not cover any damages to the radio.)

Installation Services

We offer installation services through our experienced technicians at iHelpU.Tech in Illinois if you do not want to install the upgrade yourself. Please message us for details.

International Sales

We are offering sales to most international markets. Shipping will be Through UPS, USPS, or DHL. Please message us if your market needs to be listed at checkout, and we will determine if we can add it. Some restrictions apply.