Silence the Xiegu G90-H1 Fan Stand

The xiegu G90 is a popular amateur radio transceiver and when used for digital modes can apparently get a bit warm. To help with this there is an accessory stand and fan combo called the G90-H1.

(eg from radioworld or Sinotel )

The problem is the fan the G90-H1 is not quiet (and runs all the time), but you can replace the fan with a quieter one. and/or fit an inline switch.

If you want to try a different fan then uses a 92x14mm fan. It only uses two wires so whether you have a fan with pwm control pins doesnt matter. Eg Noctua NF-A9x14 PWM.

Some write ups and advertising say “Monitored by a digital chip…” but the reality is the control circuit is a linear controller with an op amp and a thermistor.

So to make it quieter we can:

  1. Add New Fan
  2. Modify Circuit to ensure new fan starts
  3. Get back on air or hand it back to the friend you’ve modded it for

After replacing the fan with a noctua , the fan did not start every time and so to increase the fan speed at normal temperature to ensure it does start requires an increase to the gain of the circuit. One way to do this is to increase R3 (stock is 68K) or put a pot in series with it.One way to do this is outlined below and at the vid at

The mod is to cut that track that feeds R3 and put a variable resistor in series with it.

The mod and the schematic of the circuit are shown below.

You may have to adjust the fan speed to adequately adjust the G90 for your own situation. For my specific use case the replacement fan with a slightly reduced air flow does what I need. Your mileage, as they say, may vary.

The pot in place over the cut.

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