Telonics TCA-500 Combo Amp
26
PB-009289 Rev _ PRELIMINARY
TCA-500
T
HERMAL
M
ANAGEMENT
S
YSTEM
I
NTRODUCTION
The cooling system for the TCA-500 Audio Amplifier consists of two variable-speed fans and an
intelligent digital controller circuit. The speed of the fans is determined by the temperature at
multiple key points within the amplifier. The controller is designed to run the fans at the slowest
possible speed sufficient to maintain the amplifier at a safe operating temperature, and thus yield
the quietest possible operation. As the temperature of the amplifier increases, the fan speed is
increased as necessary.
N
ORMAL
C
OOLING
M
ODE
:
T
EMPERATURE
I
NDICATION
The amplifier’s temperature is indicated on the front panel via the status LED’s:
Blue
= Thermal Management System
/ AC power ON LED
is On
Green
= Temperature is above the Low temperature threshold
Yellow = Temperature is above the Medium temperature threshold
Red
= Temperature is above the High temperature threshold
The following table shows the state of the Green, Yellow and Red LED’s, and the fan speed for
the specified temperature ranges:
Notes:
‘Wink’ = short blink, once
per sec.
‘ON’ = on solid.
F
AN
S
PEED OUT OF
S
PEC
I
NDICATION
The speed of the fans is measured continuously in order to make sure that the fans are operating
properly and to assure adequate cooling for the amplifier. If the speed of any of the fans is out of
allowed tolerance for five or more consecutive seconds, then the LEDs defined by the above
table (i.e., Green
and
Yellow for temperature between Medium and High) will blink long flashes
twice per second; they will be On for ¼ second, and Off for ¼ second. This is a flash that is
easily discernible from the ‘Wink’ condition described above. If the speed of all of the fans
returns back to within tolerance, the blinking will stop, and the LEDs will return to the state
described in the table above. Should this ‘Flashing’ persist, this could be indicative of a fan
failure, and could lead to the amplifier overheating. In this case, the amplifier should be returned
to the factory for repairs.
Temperature
LED Status
Fans
>=
<
Green Yellow
Red
No.
Speed
Low
Wink
off
off
1
Minimum
Low
Medium
ON
off
off
2
Increasing
Medium
High
ON
ON
off
2
Increasing
High
ON
ON
ON
2
Maximum
