user manual
TFS-780
TFS-780 user manual
Page 48
If excess current draw is sensed either within the power supply or within the amplifier
module, for example in the event of a short circuit at the output, the fault mode will be
triggered. The TEMP LED will illuminate, and the amplifier will switch off. The power supply
will not commence the power up cycle again until the short has been removed.
Output
Output
Output
Output Should the internal circuitry not be able to maintain a low DC voltage at the output
terminals, detect high level ultrasonic signal drive or hard clip in excess of 15dB overdrive,
then the fault mode will be triggered and the power supply will be latched off ('Latched Kill').
Although the amplifier will not be harmed if it is repeatedly switched on while the fault that
caused it to power-down still persists, we recommend you investigate the system set-up and
make one or more changes before powering-up again. By doing this, you will minimise long-
term stress on the amplifier.
Troubleshooting
Spontaneous Powering-down
Spontaneous Powering-down
Spontaneous Powering-down
Spontaneous Powering-down
Symptom 1: Amplifier powers-up normally. Later on, it latches off (FAULT LED flashes).
Check the mains voltage. If the voltage was low at the time of switching-on, and has
subsequently risen (or it has been increased with a variac), an over-voltage has possibly
been detected. Assuming the supply voltage is now back to normal, simply switch the
channel off, then on again, so the amplifier sets itself to the correct AC voltage.
Symptom 2: Fan dead, LED’s not responding on one or both channels.
Check the Auxiliary supply fuse, located under the centre of the top cover plates (250mA,
20mm)
Symptom 3: Fan dead, but 4/2 Ohm & Channel Mute LED’s light up.
Check the mains supply fuse (one per channel), located under the centre of the top cover
plates (20A, 1" HRC)
Repeated Power up/down cycling
Repeated Power up/down cycling
Repeated Power up/down cycling
Repeated Power up/down cycling
Symptom 1: The amplifier powers down immediately after powering up.
Check the drive level. It is almost certainly driving the amplifier into hard clip (>0dB). For
immediate powering-up, temporarily reduce the input signal (the front panel controls are fine
for this). You can trim the level once powering-up is successfully accomplished.