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Icom HM-36 Microphone Mute Mod Member Store

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Schematic Diagram of the Icom HM-36 Microphone Mute Mod
(modification changes in red color)
Icom HM-36 Microphone Mute Mod Schematic

1. Disassemble the microphone enclosure by removal of screws.

2. Remove the PC Board and the PTT button arm, carefully retaining the PTT button arm spring in its original position.

3. Cut the jumper on the PCB as indicated in the two images below.

4a. Scrape the solder mask off the two traces indicated and add a solder blob shorting the traces...
4b. Add a small insulated jumper wire between the solder points of the traces as indicated in the image below:

5. Image of the jumper wire in place, below:

6. Image of the solder blob shorting the traces, below:

7. Final image of the PC Board modifications, below:
8. Final step. Assemble the microphone and test it.

Note #1: An older version of the Icom HM-36 microphone exists. The PC Board is different than the one in the photos and schematic presented in the modification description above, and therefore does not apply. A proposed schematic for modification of the old HM-36 design is presented below:

Note #2: Be careful not to press the UP or DOWN buttons while you are transmitting, because the UP/DOWN buttons are no longer inhibited during transmit. If you want to permanently disable the UP/DOWN buttons, simply delete the "solder blob short" part of the modification.

This modification is not approved by Icom. It is presented purely as an example for educational purposes only.

A Word to the Wise:
If you are not qualified to perform this modification, do not attempt it. You alone assume full responsibility for your own actions. No responsibility is assumed by HFLINK for the suitability of this to your application. You may damage or destroy the microphone. Failure to heed this advice may lead to you rendering the microphone worthless or unrepairable.

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