Sherbourn Technologies PT-7010A - Manual (Page 55)

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display. Keep holding the buttons down until “Resetting
to Factory Defaults” appears in the front panel display.
When the PT-7010A has been reset, it will shut off.
Turn the PT-7010A back on and it will go to the default
screen. It has now been reset. If the PT-7010A has to
be reset regularly you should invest in a good quality
AC line conditioner or contact Sherbourn for technical
support.
Problems Updating PT-7010A Firmware
• Check that the serial cable is connected correctly
between the PT-7010A and your computer’s serial port.
If you have a Palm Pilot™ or similar device with
“HotSync™” or its equivalent, you may need to disable
this software before proceeding. This software ‘seizes’
control of a serial port on your machine and prevents the
Sherbourn software from accessing that port. Use another
port or disable HotSync.
For additional information regarding technical issues
encountered with updating the firmware of the PT-7010A,
visit the Sherbourn website at www.Sherbourn.com.
“Hum” Noises
This problem is more than likely caused by a “ground loop”
in your system, rather than a fault in the PT-7010A. Follow
these steps to isolate the main cause of the hum; there
may even be more than one. Remember to turn off all
components in your system, including the PT-7010A,
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 PT-7010A 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
inexpensive device fitted in line with the coaxial cable
feed. Contact your cable company or your Sherbourn
Dealer for assistance.
• Disconnect all connections from the PT-7010A 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 PT-
7010A, until you identify the problem. (Ground loop
isolators are available for audio lines and video. Ask
your Sherbourn 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, remember that
Sherbourn’s dealers and technical support staff will assist
you.
Other Probable 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 another AC socket on a
separate line.
• If the hum is heard from within the PT-7010A 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 PT-7010A 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
tend to reveal noises which other speakers do not.