Hot radio?

Contributed by Matthew A. Erickson, KK5DR


The topic has been raised that the IC-756Pro II (or IC-756Pro III) "runs hot". I feel that this is mostly "perception", not reality.

I did a few quick tests to show real data, not a perception.

The following are the test conditions:

The IC-756Pro II has been on receive for about 3 hours; the ambient room temperature is 80°F (27°C).

During the time period, the radio was transmitted on for about 10 minutes out of each hour.

The temperature was taken with a probe-type thermometer of good accuracy. The probe was placed in the direct air-flow, or directly in contact with the metal cabinet, or both. The measurement was read after 3 minutes of probe placement.

Here are the temperatures and locations:
  1. Directly above the display in contact with vent hole; 93°F (34°C).

  2. In the air-flow, on the back panel, behind the PA section; 96 to 98°F (36 to 37°C). This will rise during TX periods.

Here is a good "rule of thumb" when in regard to solid state gear:  

Place your hand on the unit. If after 30 seconds of contact you must remove your hand due to heat discomfort, then the gear is truly "running hot". 

If you can keep your hand in place indefinitely, the gear is operating well with reasonable levels. 

Please do not let your "perception" of heat cloud the reality.

Hint for equipment installation:

My primary concern is with those operators who "stack" gear tightly, or install it in unventilated consoles. This is very tough on the gear that must "breathe".

Please read the instructions in the introductory pages of the user manual concerning proper installation of, and airflow around, the equipment. When the design engineers did the thermal budget, they did not envisage installation in an enclosed console without air circulation.

The folding supports at the front of the bottom case shell should be extended to improve airflow underneath the radio.

73 de Matt KK5DR

Contents copyright  2004-2010 M.A. Erickson. All rights reserved.
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Last updated: 09/25/2019

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