I have described a solution an overheating problem with my IC2200H at Cooling an IC2200H. The Yaesu FT2800M suffers exactly the same problem.
This article describes a thermostatically controlled auxiliary fan to keep the case at a safe temperature.
- FT2800M set to high power and connected to a suitably rated dummy load, tx latched on.
- a 125mm 12V muffin fan is secured to the top of the radio over the heatsink with a couple of elastic bands;
- an inexpensive digital thermostat (~A$13 inc post on eBay) is connected from the 12V supply to the fan, and the thermistor sensor is held against the heatsink with a wedge of foam plastic.
The thermostat set value has been programmed to 45° and differential of 5°, so the fan will start when the temperature reaches 50° and stop when the temperature falls to 45°.
Above is a video of the system sped up by a factor of 10.
Above is the system after it has been running from cold for a little while and the temperature is rising past 43.8°.
At 16s into the video, the on temperature has been reached (the WORK LED indicates that the fan is working).
At 28s into the video, 12 seconds after the last pic in the video or +120s in the real world, the on temperature has fallen to the set value (the WORK LED indicates that the fan is off).
At 45s into the video, 16 seconds after the last pic in the video or +160s in the real world, the on temperature has been reached again (the WORK LED indicates that the fan is working).