Studio Technologies ISS - Manual (Page 41)

Issue 3, June 1990 ISS User Guide
Page 42 Studio Technologies, Inc.
ISS
Setting the Left Channel AC Balance
1) Connect one of the AC voltmeters
between COM and the left channel
audio high connection, test point B+
on Extender Card 2. Connect the other
AC voltmeter between COM and left
channel audio low connection, test
point B– on Extender Card 2.
2) Set pot R29 to give equal amplitude
on the two meters. You should be able
to adjust the balance within about 10
millivolts.
Setting the Right Channel Balance
1) Move the signal generator output to
the ISS right channel line input.
2) Connect one of the AC voltmeters
between COM and the right channel
audio high connection, test point D+
on Extender Card 2. Connect the other
AC voltmeter between COM and right
channel audio low connection, test
point D– on Extender Card 2.
3) Set pot R28 to give equal amplitude
on the two meters. You should be able
to adjust the balance within about 10
millivolts.
4) This ends the procedure.
Aligning the Crossfade Card
The Crossfade Card contains two potenti-
ometers. These are set to provide the
maximum attenuation of the input signals
from the Type I and Type II Simulator Cards
when the ISS is in the bypass mode. One
pot is set for each of the two channels.
Materials Required for Alignment
• ISS Extender Card System (two cards
and two cables)
• Low Distortion Audio Signal (Sine Wave)
Generator
• Audio Voltmeter with high impedance
input (AC VTVM)
• DC Voltmeter, high input impedance type
• Test Probes for above
• 10k ohm, ¼W Resistor
• Jumper wire with test clips at each end,
6-inch maximum length
Procedure
1) Place the Crossfade Card onto the
Extender Card System. Refer to the ISS
Technical Manual for Extender Card
installation details.
2) Turn the ISS mains power on.
3) Set the ISS to: I/O Normal, mode to
MAN, BYPASS.
4) Set the signal generator output fre-
quency to 1kHz, level –6dBu.
Checking the Power Supply Voltages
With the DC voltmeter common lead con-
nected to COM test point: check +15 test
point for +15 ±1Vdc, +24 test point for
+24 ±1Vdc, and, –15 test point for –15
±1Vdc.
Checking the Ramp Voltage
With the DC voltmeter common lead con-
nected to COM test point: check RAMP test
point for 0Vdc ±0.050Vdc. This insures you
are in the bypass mode.