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Icom IC-2820 RX Fan Silencer Mod


Staff member
Apr 6, 2005
Nor Cal Sierra Nevada
I use my IC-2820 mainly for RX. Annoying is the FAN, which swiches on / of during the day, and produces a lot of noise, while i do not find the Icom 'hot' or even 'warm'.
Icom designed the fan circuit in such a way, the fan switches on at approx 28 degrees C. I dived in the circuitry, and found a way to lift this temperature to approx 35 degrees C.
The mod if fairly simple, by just replacing a resistor, however the difficulty rate goes sky high if you see how large the resistors are these days.
We are talking about R510 on the main unit. The resistor is located under the speaker, and can be accessed by lifting the top cover, and removing the speaker. At the top of the diagonally placed IC25 you will find the resistor. It is attached to PIN 71 of IC25.
I marked the resistor in RED on the picture below.
You can do 2 things:
  1. Replace the resistor (originally 39 kOhm) with a resistor of 22 kOhm.
  2. solder a resistor in parallel with the original one.
    in that case, you don't have to remove the very small original resistor, and thus can make things easier. You will need a resistor of 56 kOhm to use this method.
If you successfully modified the IC-2820, you will never hear the fan again in normal circumstances.
My fan is silent for over 6 months, and my rig works just fine.

DISCLAIMER: Your mileage may vary, i am NOT responsible for ANY damage or faults. Modify your rig at your OWN RISK.

just ordered the 22kOhm resister from digikey that matches the one used in the unit from the factory (except for the value). Any tips on soldering it in? removing them seems straight forward enough but I've never added SMD components before. I hear there is certain resin paste that is helpful....
I wish that I could help, but I can't.

I hope that you get some replies. I wouldn't expect it, though.
We often find Modifications for radio`s by searching the Net, and bringing them here for the Members.
I try to give credit for the Mods when possible, in this case I do not remember who sent me this Mod, I have not done it myself, therefor no pictures.

A lot of people have fixed the red/yellow ring of death on their Xbox/PS3 by using a heat gun to reflow the solder. IF I were to attempt this mod on my 2820 that would be the method I would use to remove/replace the resistor.
I have read, somewhere else, that people are installing a different fan. According to what they said, (and I can't remember where it was), the fan in the 2820 is a common size and they replaced it with one from a laptop, or something else.

That sounded like a better idea, concerning my soldering skills....
I'm going to attempt to replace the resistor today using a hot air rework station and some syringe dispatched solder paste. I'll try to post pictures and the results later.

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