User's Manual

40 Functional Description TB7100 Installation and Operation Manual
© Tait Electronics Limited December 2005
3.5 Fan Operation
The cooling fans are mounted behind the front panel. All fans in the chassis
must be of the same type.
Dissipation of Heat Heat needs to be dissipated from a number of components within the
internal AC power supply unit, transmitter and receiver modules, including
the following:
■ 9V regulator
■ RF PA
■ driver for RF PA
■ audio PA
The mechanisms by which the heat is conducted away in each case are
described below.
Dissipation of Heat
from Transmitter
The transmitter board is mounted directly onto a heatsink through which
the forced air from the fans is ducted.
Dissipation of Heat
from Regulator and
Audio PA
Heat from the audio PA and 9V regulator on the receiver board is conducted
away by a small aluminium heatsink and mounting boss. The heatsink and
boss contact the underside of the board where the components are mounted
and thermal paste ensures a good thermal transfer between the two surfaces.
Dissipation of Heat
from RF PAs and
Driver
Heat from the RF PAs and driver is conducted to the heatsink through a
copper separator plate. The copper plate is fixed to the underside of the
board and the components soldered directly to it. The copper plate is
mounted directly to the main heatsink boss and a coating of thermal paste
ensures good thermal transfer between these two surfaces.
Dissipation of Heat
from Internal AC
Power Supply Unit
Air is forced round major components within the internal AC power supply
unit to keep them cool. Some air is passed through a small heatsink to keep
the current-carrying semiconductor devices cool.