Cooling - Kenwood TS-990S In-Depth Manual

09 TECHANICAL STRUCTURE
The external dimensions are 165 mm high (+24 mm) x 460 mm wide (+58 mm) x 400 mm deep (‑5 mm) (6 1/2 in high
(+15/16 in) x 18 7/64 in wide (+2 9/32 in) x 15 3/4 in deep (‑13/64 in)).
The values in the parentheses indicate the measurements compared with the TS‑950. The panel size is wider than that
of the TS‑950; however, the depth is shorter by 5 mm (13/64 in).
For the high‑density mounting of a number of boards in the chassis, partitions are placed and the boards are secured in
the partitions. The partitioned structure serves to give shielding effectiveness by the walls of the partitions.
Fig. 5 Chassis (Bottom Surface)
Fig. 5 Chassis (Upper Surface)

Cooling

The TS‑990S has a final unit which is cooled by a crimped fan radiator.
Water‑cooling radiators, heat‑pipe radiators, and other various types of radiators were examined, and the radiator
on which the radiating fins are crimped was chosen because of its excellent balanced features concerning cooling
capability, weight, operating noise, and reliability. The water‑cooled structure is superior in cooling capability, but is not
suitable for a transceiver that may be subject to long‑term operation without maintenance.
Fig. 5 Radiator Fig. 5 Heat Pipes
Fig. 5 Water‑Cooling Head
The TS‑990S has five internal cooling fan motors. The fans are respectively placed for the power supply unit, final unit,
and antenna tuner unit zones, and the TS‑990S air breaths from the sides and bottom to cool the inside with the air by
the fans. The cooling system is designed for simplicity.
The motor of the fan for the final unit has a 3‑step operating mode to secure less noise by the operation of the final unit.
Even if the temperature rises to an unexpected degree, a protection function activates and reduces the transmit power to
secure protection against malfunction.
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