Crown IQ System User Manual
Rev 3-97
* School
IQ System Troubleshooting
OVERVIEW
The purpose of this chapter is to provide detailed information about system
level troubleshooting of IQ Systems. Most problems with IQ occur at the time
of installation. Good installation techniques take care of most problems before
they happen. This chapter provides some installation tips, but it assumes little
about the quality of installation techniques. It is also important to remember that
how well a system sounds or operates depends heavily on good system design
and installation. The best troubleshooting skills may do very little for a poorly
designed audio system. This chapter deals with troubleshooting IQ components from a control standpoint, not audio performance.
OBJECTIVES
At the completion of the lecture and labs for this chapter the student should be
able to meet the following list of objectives:
• List the steps of universal troubleshooting techniques.
• Describe each step of universal troubleshooting techniques.
• State the most common installation problems encountered with IQ.
• List the configuration parameters that must match between software and
interface hardware.
• State the maximum operating length RS232 and RS422.
• State the maximum loop capacitance for normal Crown Bus operation.
• State the valid range of loop addresses.
• Explain what a valid component identification is.
• List the software functions that can be used to troubleshoot IQ.
• Explain how Roll Call is a troubleshooting tool.
• Describe the proper method of taking a voltage measurement to check
Crown Bus wiring.
• State the expected voltages for normal, open, shorted, and reverse polarity
Crown Bus wiring.
• Describe the proper method of taking current measurements to check
Crown Bus signal waveforms.
• State the minimum current for a current high and the maximum current for
a current low.
• Explain how software break detection works.
• List the most likely reasons why you might see an Interface Not Found
message.
• List the most likely reasons why you might not find components on a loop.
• Explain what happens to loop communication when an IQ component loses
power.
• State what resources are available to help you troubleshoot an IQ problem.
Notes
SLIDES
1. Universal Techniques
• Symptom Recognition
• Symptom Elaboration
• Probable Faulty Block
• Probable Faulty Function
• Repair
• Retest
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2. Common IQ Problems
• Swith configuration
• RS232/422 cables
• Non-standard serial ports
• PC does not meet requirements
• Software configurations
• Design error or campatability problem
• Crown Bus wiring errors
• Crown Bus capacitance
3. Troubleshooting Tools
• Roll Call (File|New)
• Engage/Upload
• Break Detect
• Voltage Measurements
• Current Waveform Measurements
• Documentation
• Technical Support (1-800-342-6939/219-294-8200)
4. Voltage Measurement: OK
Figure 1
5. Voltage Measurement: Shorted
Figure 2
6. Voltage Measurement: Open
Figure 3
7. Voltage Measurement: Reverse Polarity
Figure 4
8. Current Measurement
Figure 5
9. Does The Software Run?
• PC Requirements
• Environment (Windows, DOS...)
• Corrupt or Incorrect Files
10. Is It Possible to Run a Roll Call?
• Demo Version
• Serial Port Parameters
11. No Interface Found?
• Interface off/unplugged
• RS232/422
• Serial port setup in software
• Interface setup
• Windows Control panel setup
• SMX in CLN mode
• RS232 smart switcher
12. Are All Components Found?
• Software support
• OIF/DLL files
• Interface compatability
• Power
• Loop wiring
• Capacitance
• Duplicate or invalid addresses
13. Factory Support Issues
• Hardware serviced only at Crown
• Upgrades
• Licensing of software
• Development products
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UNIVERSAL TROUBLESHOOTING TECHNIQUES
There are some basic procedures which apply to troubleshooting at any level,
whether it be component level circuit board repair or very general system level
service.
Symptom Recognition
The first step in troubleshooting is to determine that a problem really exists. All
too often a problem exists in a system that is never identified and never fixed.
The long term result is an unsatisfied customer. On the other hand, a system
operator may expect a certain result and feels that there is something wrong
with the system when he does not get that result. Recognizing symptoms of an
actual problem may be very obvious or may be quite subtle. In either case a
solid understanding of how an IQ System operates is critical to determining if
a problem is real. Symptom recognition, then, is the determination that a
problem exists by virtue of the system response being different from the
expected response.
Example: Amplifiers in equipment room #1 do not respond to commands sent
from the computer.
Symptom Elaboration
Once you decide that a problem exists you need to try to find out as much about
the problem as possible by examining the nature of the symptoms. This step
in the process often involves some very basic testing to get you looking in the
right general area for the exact problem. Specifically is the process of defining
the exact nature of the problem.
Notes
Example: When taking a Roll Call all components appear except those in
equipment room #1.
Probable Faulty Block
Once you have gathered all the information you can about the specific nature
of the problem you can usually determine where to start looking. This step often
involves checking your symptoms against system documentation.
Example: Examine system prints and find that component in equipment room
#1 are all on Crown Bus loop 3 and they are the only components on loop 3.
Problem is likely to be a communication problem somewhere in loop 3.
Probable Faulty Function
At this point it is often necessary to use your troubleshooting tools to break the
problem down until you find out exactly what the problem is.
Example: Visually inspect cable connections for loop 3 at the interface and in
the equipment room. You locate a Crown Bus cable that has been pulled loose
from a PIP data input at Amplifier 13. An alternate method of testing if the DOS
software is used is to run a SEARCH on loop 3 using the IQ software. It would
reveal a “Break on loop 3 before Amplifier 13.” This would tell you where to go
to physically look for a cable problem.
Problem Verification & Repair
The final step once the problem is found is to fix it and test the system. There
have been times in every technician’s life where they think they have found the
problem, performed a repair, and found that something else was wrong. It is
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very important to verify that the system is, in fact, working after you perform a
repair.
Example: Plug the cable back into the PIP then run a Roll Call to verify that all
system components are on line then verify that the amplifiers respond to
commands sent from the computer.
COMMON IQ SYSTEM PROBLEMS
Most IQ System problems occur at the time of installation. Most of those are
related to hardware or software communication setup. Other than hardware or
software settings, loop capacitance is a significant factor. In many cases wire
selection is becomes a critical factor. In longer loops where capacitance is
questionable it may be necessary to add an IQ-RPT Repeater to the loop.
Hardware Setup
Switches are a necessary evil in the setup of any IQ System. Component
addresses must be a valid value with no duplicates of same type of component
on the same Crown Bus loop. Baud, parity, and any other hardware switch
settings on the component serving as system interface must be properly
configured. Parity should, except in very unusual circumstances, be off. The
computer, software, and RS232/422 cable must be capable of supporting the
baud selected at the interface. AC power must be available and the interface
must be on. RS232/422 cable must be connected at both ends to the proper
computer serial port as well as the proper IQ System component. You must
have a 16550 UART for the computer com port. The computer itself must meet
the minimum requirements for the type of software being used.
IQ components are not likely to fail, but it is not impossible. Lightening is a
respecter of no one. The most common type of hardware failure is opto-isolator
damage due to high voltage spikes from lightning or other power sources. The
only other major source of hardware failure is failure to follow proper static
handling procedures of components with exposed static sensitive electronics
such as PIP module and card cage components.
Software Setup
Most software parameters that affect whether or not you can communicate
properly with the system in DOS software are found on the F10 control panel
screen. In IQ For Windows both the program communication settings and the
Windows Control Panel effect communication. At a minimum those settings
include com port enable, com port number, IRQ number, Base Address, and
baud.
Crown Bus Loop
The Crown Bus is a communication standard based on the transmission of
proprietary IQ command protocol on a serial data loop. Although other media
may be used to transmit the protocol, IQ hardware uses 20 ma current as the
media to go into and out of components. Digital signals are, by their nature,
simply pulses of DC. This in turns means that data signals are polarity sensitive.
One of the most common mistakes made when wiring Crown Bus connections
is to reverse the polarity of a Crown Bus cable. A broken or unplugged cable
or polarity reversal anywhere in the loop consitutes a break in the loop. When
the IQ-INT II unit is used as the interface a common problem is to have the input
and output lines for one loop connected to the interface output of one loop and
the input of another loop at the interface.
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Cable capacitance is another issue. In general Crown recommends that you
keep maximum loop capacitance at 30 nF or less, although in most cases a loop
will operate properly at up to 40 nF. To calculate loop capacitance add up the
total loop wire length, multiply that by the capacitance per foot (or meter) rating
of the cable used, and add 60 pF per component on the loop. Restart the
calculation at the output of each Repeater in the loop. RFI is rarely a problem
with twisted pair Crown Bus cable because the Crown Bus is usually a 20 ma
current loop. Induced noise may, however, be a consideration.
PROBLEM PREVENTION (INSTALLATION TECHNIQUES)
Good installation techniques will save you a great deal of trouble after the
installation is thought to be complete. The best way to install a large IQ System
is to test the system a rack at a time, then add racks to the loop(s) one at a time.
This may seem more time consuming, but in a large system you may save hours
of work later by running a ten minute check in the equipment room.
Always use proper static handling procedures. Never pull a PIP module out or
put one into an amplifier if the amplifier is powered up. It is best to always unplug
the amplifier and wait a few seconds before taking a PIP card in or out. If you
are involved in a situation where firmware is being upgraded always ensure that
a trained technician performs the actual chip replacement.
When you setup a component one of the parameters you always have to deal
with is the component address. To save time later it is always recommended
that you mark components with their loop address and annotate system
drawings to accurately reflect those addresses.
Notes
TOOLS AVAILABLE
There are many resources available to troubleshoot an IQ System problem. The
software has a number of powerful features, the hardware also has valuable
tools built in. A good visual inspection finds many problems before you have
to use any equipment or software. Basic test equipment such a voltage meter
can tell you a great deal, and if all else fails you can always resort to checking
documentation.
Roll Call
Roll Call is the first and most important tool you have in the software. When you
run a Roll Call the software establishes communication, first with the interface,
then each component on each loop of the interface. The Roll Call reports status
step by step. It gives you status of communication with the interface, running
status of components it finds, and inventory totals. Note that all the inventory
information in the world is of little value unless you know what you are supposed
to find. It is critical that you know what the inventory should be. You should be
able to run a Roll Call and find all the components that are connected into the
system, and you should be able to get that inventory consistantly.
When you perform a Roll Call the software establishes RS232 communication
with the interface first. The interface is interrogated and must report its identity
as a component type. This process must be completed before any further steps
may be taken. Even if the software you are using does not support the
component serving as system interface, the software should recognize that an
unidentified component is the interface.
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ONLINE Indicator
After running a Roll Call and finding components you need to be able to
maintain communication with the system. Each component has an ONLINE
indicator available in the software. This indicator is a software tool that lets you
know you are in contact with the desired unit. If the ONLINE indicator goes off
you should be able to reestablish contact by running a Roll Call, using
Control+E, loading a dataframe file, or by using On Line Search.
Engage (^E)
If you have either had and lost communication or you have loaded a dataframe
without successfully communicating you may engage the dataframe by using
Control+E. This key combination engages the dataframe and forces all the
settings in the software out through the com port of the computer. The settings
for each component that are in the inventory of the dataframe file will be forced
to the system. If the system is there and all loops and communication pathways
are intact all settings should be engaged and all components should come on
line. Part of the process of engaging the dataframe is to check each component
in the inventory and ensure that they are present and on line.
On Line Search (DOS Software Only)
The On Line Search feature, found on the F10 control panel screen, performs
a function which is similar to Roll Call. When you run a Roll Call the system takes
an inventory, uploads component settings, and fills in control blocks with data.
When you use On Line Search the software compares the inventory against the
actual system. This is done automatically at regular intervals. It serves to
automatically refresh On Line indicators. If a component drops off line for some
reason, such as power loss, the On Line Search feature will automatically
reestablish communication with that component when power is restored. It will
also restore communication to a whole loop of components if the loop becomes
broken and is later restored. While the software contains more components in
its inventory than are actually on line this feature will cause the software to
temporarily pause while the on line search is in progress.
6 — Troubleshooting
On Line Search is the feature you want to use to build a dataframe file manually.
When a component is added to a dataframe manually the on line search feature
not only finds the component and brings it on line, but it also uploads the
settings from the component into the software and makes any changes
necessary to settings in the dataframe. On Line Search will upload settings
even if you are only reestablishing communication. On Line Search is a feature
that may be turned on and left on at all times in many systems, but it is important
to understand the effects of this feature so that the software does not surprise
you. Note that On Line Search does not actually locate or identify breaks; it
continuously verifies the dataframe inventory.
Break Detect
Break Detect is a feature that can be switched on at the F10 control panel screen
of DOS software; it is always on in IQ For Windows. It allows the software to
automatically listen for signals from components that identify breaks. Before
you can understand what this feature really does it is important to understand
what happens in the system when a break occurs in the Crown Bus loop.
All IQ components sense Crown Bus data input continuity. A logic low is actually
a high current condition and a logic high is a low current condition. When a
component goes for a period of time without seeing a high current (more than
12 milliamperes) input the unit recognizes the condition as a break in commu-
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