How hot is too hot?

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  • Updated 5 years ago
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Just got the 6300 setup for digital modes today.  I worked a PSK station for about 10 minutes and noticed DDUil was registering 57 degrees C after a long transmit.  Is that normal?  My radio seems to sit around 40 degrees C in standby.  The radio didn't feel hot and I don't think the fan sped up.    Seems to run hotter than my 5000.  I just want to make sure I'm not hurting anything.  The temp was still in the green mode/background on DDUtil.

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Burch Akin

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Posted 5 years ago

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Steve - N5AC, VP Engineering / CTO

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Official Response
The two chassis fans which pull air across the PA heatsink will switch from low speed to high speed at 70C.  They will return to low speed at 55C.  This temperature is measured on the flange of the transistors and is not exact, but it is close.  The absolute maximum for the transistor is spec'ed at 175C for the "channel" which I suspect is the junction temp.  Graham is really the expert on PA transistors and could give better recommendations on what you should be comfortable running the part at, but I wouldn't be concerned about running them at 100C.  As you may have noticed, the fans and the heat sink are very good at removing heat from the cabinet and the temperature will drop rapidly when you unkey the radio.