Zeck Audio STAC Force180 Owner's Manual - page 13
5.4 Bridge Mode (Fig. 4.3)
When the bridge mode switch (14) is in its
BRIDGED MONO position, both stereo output
amplifiers inside the FORCE 180 are combined for
monaural operation, doubling the available output
power from 300W to 600W. Refer to chapter 4 for
correct input connections for bridged operation.
Attention:
Switching the FORCE 180 to bridge
mode also doubles the speaker output impedance
from 4-8 ohms to 8-16 ohms. For maximum power
efficiency, the total speaker impedance should
always equal the amplifier's output impedance.
13
Owner`s manual FORCE 180 STAC Audio
FORCE 180
BRIDGED
MONO
STEREO
7. Troubleshooting
Symptom
Problem
POWER LED (13) remains dark after
- Blown house fuse(s). Check and replace fuses.
POWER switch (12) has been engaged.
- Internal power supply defective. Contact authorized STAC
dealer.
- Automatic amplifier fuse (17) has been triggered. Reset fuse
by pushing button.
PROT LED (9) remains bright
- Check speaker cables for short connections.
- Check speakers for short connections or incorrect wiring.
- Insufficient cooling air supply or amplifier overload.
(Contact authorized STAC dealer)
- Amplifier defective. (Contact authorized STAC dealer)
SIGNAL LED’s (6 oder 7) remain dark and
- Check connections between amplifier inputs and mixer.
P O W E R L E D (12) is bright.
- Check audio device before amplifier.
SIGNAL LED’s (6 & 7) are flashing, but no signal is
- Check connections between amplifier outputs and speaker
heard.
cabinets.
- Check position of VOLUME controls (10 & 11)
- Check speakers for function.
A loud hum is heard through the speakers.
- Move ground switch (15) to other position.
5.5 Protection functions
A bright PROT LED (9) indicates that one of the
FORCE 180's internal protection circuits has been
activated. The reasons could be:
- DC voltage at the speaker outputs
- Short circuit at one speaker output
- Overload of amplifier
- Mismatched speaker load
In this case, switch off the amplifier and check all
connections. If the PROT LED remains bright,
contact an authorized STAC dealer.
5.6 Cooling
The FORCE 180 has two independent cooling fans
for protecting both output amplifiers against
overheating.