Studio Technologies 81 - Manual (Page 12)

Issue 1, January 2000 Model 81 User Guide
Page 12 Studio Technologies, Inc.
you a visual indication whenever audio
signals are present on the Model 81’s
input.
The LEDs labeled Lo will light whenever
an input signal is within the range of 18dB
below and 0.5dB above the nominal oper-
ating level. The LEDs labeled Hi will light
any time an input signal is greater than
0.5dB below the nominal operating level.
This sounds a bit confusing but isn’t really
so hard to understand. As an example,
if you have a nominal “+4” signal con-
nected to the Model 81’s line input and
the ExactCal section has been used to
calibrate the input, the Lo LEDs will light
whenever the signal is between –14 and
+4.5dBu, the Hi LEDs will light whenever
the signal exceeds –3.5dBu.
The eight outputs are fully independent.
You can patch, reconnect, or even short
out an interconnecting cable without
effecting the other outputs. Using the
front-panel DIP switches you can change
the output level of any or all of the outputs
whenever you wish.
Remember that if you change the input
source you may need to use the ExactCal
section to recalibrate the input. Refer to
the configuration section of this guide for
details.
Troubleshooting
If you’re having problems getting the
Model 81 up and running, this section can
help. If you haven’t read the other sections
of this guide, you should do so before
proceeding.
If the Model 81 Doesn’t Work At All
A source of AC mains power must be
connected to the Model 81. Depending on
the version you have purchased, 100, 120,
or 220-240Vac, 50/60Hz is required. Con-
firm what mains voltage is required by
observing the selection boxes to the left
of the AC mains connector on the back
panel. Whenever mains power is con-
nected the front panel power present LED
should light. If the LED is not lit confirm
that AC mains power is active (“hot”) and
that the cord is securely mated with the
connector on the Model 81's back panel.
For safety in the event of a major internal
failure or the connection of incorrect AC
mains voltage, the Model 81 contains a
fuse inside its cabinet. The fuse will open
(“blow”) if the failure of an internal compo-
nent causes excessive current to be drawn
from the internal power supply. The fuse
will also open should 220-240Vac be
connected to a Model 81 that is config-
ured for 100 or 120Vac operation. The
fuse is intended to be replaced only by a
competent service technician. This person
will have the training to safely access the
“guts” of the Model 81 and identify where
a problem is located.
Incorrect Output Levels
You must correctly set the input trim pots
so that the eight stereo outputs can pro-
vide precise –10dBV or +4dBu nominal
output levels. These trim pots are used to
match the nominal level of the audio input
signal with the Model 81’s internal cir-
cuitry. Refer to the Configuration section
of this guide for detailed instructions.