Studio Technologies 80 M80-00273, User Manual

Page: 10 / 17

Model 80 User Guide Issue 4, March 1997
Studio Technologies, Inc. Page 13
If the Model 80 Doesn’t Work At All
A source of AC mains power must be
connected to the Model 80. 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 the main power source is active
(“hot”) and that the connector on the
cord is securely mated with the plug on
the back panel.
For safety in the event of a major internal
failure or the connection of incorrect AC
mains voltage, the Model 80 contains a
fuse inside the 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 80 that is config-
ured for 100 or 120Vac operation. The
fuse is intended to be replaced only by a
qualified service technician. This person
will have the training to safely access the
“guts” of the Model 80 and identify where
a problem is located.
Incorrect Output Levels
You must correctly set the input level
and right trim controls for the eight stereo
outputs to receive a precise –10 or +4dBu
nominal output level. These controls
match the level of the audio input signal
with the Model 80’s internal circuitry. Refer
to the Configuration section of this guide
for detailed instructions.
Intermittent Audio Connections
Should you experience audio connections
that seem to be “flaky” or intermittent,
refer to the Technical Notes section of
this guide. The ¼-inch 3-conductor phone
jacks used on the Model 80 are of very
high quality, conforming to the industry
standard EIA RS-453. Some plugs do not
meet this standard, specifically in the
shape of the tip conductor. In rare cases
you may have to replace plugs on inter-
connecting cables to remedy an intercon-
nection problem. Switchcraft No. 297 or
Neutrik NP3C phone plugs will function
correctly.
Headphones as a Troubleshooting Tool
One of the simplest means of checking
for the overall presence of a line-level
audio signal is to “listen” to the signal
using a pair of stereo headphones. The
signal level and source impedance of
contemporary audio output circuitry can
easily drive headphones to quite a high
sound pressure level. Carefully used,
headphones are a great means of rapidly
determining if signal is present on an
audio line. Note that in a few cases the
plugs used by headphone manufacturers
do not comply with the EIA-453 specifica-
tions for ¼-inch plugs. You may want to
designate a pair of headphones for line-
level testing and attach a plug of known
quality. We have found that even some
very high quality headphones have non-
standard plugs; be warned!
Warning: Safety First! Do not plug a
pair of headphones into a jack on the
Model 80 while the headphone ear
pieces are against your ears. High
sound pressure levels may be present.
Only after a signal is connected should
you slowly put the headphone trans-
ducers near your ears!