Studio Technologies ISS - Manual (Page 23)

Issue 3, June 1990 ISS User Guide
Page 24 Studio Technologies, Inc.
ISS
14) You are now ready to turn the ISS
power switch to the ON position and
perform your required procedures.
Some minor cross talk or hum pickup
can occur due to the physical positions
of the ribbon cables connecting the
mainframe to the card being serviced.
Avoid placing the ribbon extension
cables (especially the 20-position) and
the card near strong magnetic fields
(such as near the ISS power supply)
that could induce hum or noise. Simply
moving the ribbon extension cable(s)
should clear up any major problems
encountered. The short interconnecting
distances on the actual ISS minimize
the chance of undesirable pickup under
operating conditions.
15) A service hint is to always begin testing
by checking the power supply voltages
that are easily accessed on the Ex-
tender Card 2 test points.
16) When storing the ribbon extension
cables, avoid sharp bends in the cable
which can cause permanent damage.
17) Feel free to call Studio Technologies
with any service or operation questions
you may have.
Technical Description
In this section, we will first review the ISS
system architecture. This will give an outline
of how the ISS relates to the outside world,
and how the circuit cards work together.
Then we will review the functionality and
circuitry contained on each ISS circuit card.
This information should greatly assist you in
understanding the operation of the ISS, as
well as providing a guide to troubleshooting
problems that may arise.
ISS System Architecture
As a complete unit, the ISS consists of a
mainframe, Transfer Relay Assembly, circuit
cards, ribbon cable bus, and front panel.
Studio Technologies chose to utilize a
commercially available powered mainframe.
By using a “stock” mainframe, the customer
benefits by getting the reliability that a
product built in quantity supplies; this
powered mainframe design is completely
field proven with thousands of units in
operation. The mainframe, manufactured by
dBx, Inc., includes a sophisticated power
supply and card slots for nine circuit cards.
The ISS circuit cards were designed to
mechanically and electrically interface into
this mainframe. Associated with each card
slot is a 10-position screw terminal strip
located on the mainframe back panel. All
connections to the Transfer Relay Assem-
bly, i.e., audio signals, remote control
inputs, and status relay outputs, are made
via these screw terminal strips. Five con-
nectors on the back of the Transfer Relay
Assembly interface the ISS with the outside
world. Connections are made between the
circuit cards using a ribbon cable bus
assembly. The ribbon cable bus assembly
consists of a length of 20-conductor flat
ribbon cable (commonly used in the com-
puter industry) with eight 20-position sock-
ets installed evenly along the length of the
ribbon cable. The sockets on the ribbon
bus connect with connectors located on
each of the ISS circuit cards. All connec-
tions on the ribbon cable bus go to every
card in the ISS. A circuit card uses only
those signals on the ribbon cable bus that
are needed. The signals on each of the 20