Model 50/51 User Guide
Issue 6, September 2004
Studio Technologies, Inc.
Page 31
If the LED does light, troubleshooting
should prove quite simple. Begin by
disconnecting the cable that is plugged
into the talent amplifier output connector.
Perform the disconnection directly on the
Model 50’s back panel. The LED should
stop lighting. Now check through all the
wiring to determine where the short circuit
condition is located. The Model 50 will not
be damaged if the Over Current LED is
lighting so you should use it to help you
locate the fault in your system. In just a
few minutes you should be able to isolate
exactly what cable or talent amplifier is
causing the problem.
Control Console Over Current LED
During normal operation the control con-
sole Over Current LED should not be lit.
It will flash on and off if the power source
that supplies the Model 51 Control Con-
sole is loaded to exceed its maximum
output current. The most common reason
for an over current condition would be a
shorted 5-conductor MIDI-style intercon-
necting cable. A major fault in the Model
51 would also cause the LED to light.
If the LED does light, you should find
troubleshooting very easy. Begin by dis-
connecting the cable that is plugged into
the Control Console/MIDI In connector
on the Model 50’s back panel. The LED
should stop lighting. Reconnect the
cable to the Model 50 and disconnect the
cable’s other end from the Model 51. If
the LED still lights you have a bad cable.
If the LED does not light there is a problem
with the Model 51. Replace the cable if it
proves to be bad—remember you’ll need
a MIDI-style cable with all five conductors
connected. If the Model 51 appears to be
at fault it will need to be returned to the
factory for repair.
Input Data LEDs
The Model 50 Central Controller’s front
panel contains two LEDs that represent in-
coming data. The Bus LED lights any time
valid MIDI-compatible data enters the unit.
The Model 50 LED lights only when data
is received that is valid for the Model 50.
The Model 50 uses MIDI system-exclusive
messages to perform all operations. When
the Model 51 Control Console is con-
nected to the Model 50, both data LEDs
will light any time the Model 51 generates
data. This is because the Model 51 will
only generate data that is compatible with
the Model 50.
If you are not using the Model 51, and
instead are supplying MIDI data using
another device, the LEDs should prove
extremely useful when troubleshooting.
Once the Model 50 is connected to a
data bus that is carrying MIDI data, the
Bus LED will light whenever
any
MIDI
data is received. Only when the MIDI data
conforms to the Model 50’s MIDI system-
exclusive format will both the data LED’s
light. If the Bus LED lights, but the Model
50 LED does not, this indicates that the
data is not configured correctly for the
Model 50. Refer to Appendix A, located
at the end of this guide, for details on how
data must be sent to the Model 50.
Clicks in the Audio
As covered in the Configuration section
of the guide, the seven stereo line inputs
can be configured for –10dBV or +4dBu
operation. Setting an input for –10dBV,
while connecting an audio source with a
+4dBu nominal level will lead to distortion
(“clipping”) of the signal. In this fault con-
dition the user would hear a harsh “click-
ing” sounds in the audio, especially when
peak levels occur in the program material.
