Sunfire Theater Grand Receiver TGR-401-230 - Manual (Page 55)

User's Manual
55
APPENDIX
Updating firmware problems
• See page 52
• If you have a Palm Pilot™ or simi-
lar device with “HotSync™” or its
equivalent, you may need to dis-
able this software before proceed-
ing. This software ‘seizes’ control
of a serial port on your machine
and prevents the Sunfire software
from accessing that port. Use an-
other port or disable HotSync.
• Check that the serial cable is
connected correctly between the
TGR-401 and your computer's se-
rial port.
A Hum is heard in your speakers
This problem is more than likely
caused by a “ground loop” in your
system, rather than a fault in the TGR-
401. Follow these steps to isolate the
main cause of the hum, there may
even be more than one.
• Remember to turn off all compo-
nents in your system, including the
TGR-401, before disconnecting or
connecting any cables.
• Disconnect the following items in
order, and check each time if the
hum has gone away:
• Disconnect all cables which come
from outside the room, such as
cable TV, satellite TV, or roof top
antennas. Make sure that they are
disconnected where they first enter
the room, so they are making no
connection to the TGR-401 or the
TV, or any other component. If the
hum is caused by the cable TV
line, then you will need a “ground
loop isolator.” This is an inexpen-
sive device fitted in line with the
coaxial cable feed. Contact your
cable company or your Sunfire
Dealer for assistance.
• Disconnect all connections from
the TGR-401 to your TV.
• Disconnect any component which
has a grounded power cord.
• If the hum persists, disconnect all
the source components one at a
time from the back of the TGR-
401, until you identify the problem.
• Ground loop isolators are available
for audio lines and video. Ask your
Sunfire Dealer for assistance.
• Try moving the speaker cables
away from any power cords. Try
just one speaker, connecting it to
different channels and see if an
amplifier channel is bad.
• If you are still having a problem,
Sunfire’s dealers and technical
support staff will assist you.
Other causes of noise
• Speaker noise may also be caused
by interference or noise on your
AC line. Make sure there are no
large appliances sharing the line,
or halogen lamps or light-dimming
Triac devices.
• Try connecting your system to an-
other AC socket on a separate line.
• If the hum is heard from within
the TGR-401 and not through the
speakers, this may also be caused
by interference on the AC or DC
lines. The power transformers
may turn this interference into an
audible noise. Internal hum can be
made worse by a shelf or cabinet
resonating, so try moving the TGR-
401 to another shelf.
• Try moving your components further
away from the TV, especially if
you ever notice the screen has
changed color in the area closest
to the component.
• If you have very high efficiency
speakers, these may show up
noise which other speakers may
not.
General notes
Check the following to get the best
out of your TGR-401:
• Each speaker's average imped-
ance is not less than 4 ohms.
• The TGR-401 has good ventilation,
and none of its vents are covered.
• Try setting all the speakers to 90
Hz, and let your subwoofer handle
the heavy bass.
• Check that the amplifier power
output is a good match for your
speakers. If your speakers are
inefficient, consider using an exter-
nal power amplifier.