CHAPTER 17

After completing and handing over an audiovisual (AV) project to the client, the project’s working life begins in earnest, providing AV services and facilities to the end users. Most installation contracts include a period of warranty for the installed equipment and its configuration. Some also include an allocation of technical support hours during the bedding-down period for the new installation.

The AV installer’s duties may include supporting the installation by diagnosing and resolving any equipment, configuration, or operational problems that may arise during the entire working life of the system. They may also be responsible for maintaining the system in optimal operating condition through a preventive maintenance program that preempts the faults and failures that can arise through the normal use and operation of the installed system.

It is important that both you and the client have a clear understanding of the extent of the contractual arrangements to provide warranty support, operational support of the facilities during the post-warranty life of the installation, preventive maintenance to reduce the likelihood of operational failures during the life of the installation, and modifications and upgrades to the installation that are outside the scope of the original system installation contract.

Your tools of installation trade include some potentially dangerous devices that can slow you down and cause you harm if not well maintained and some test and measurement devices that need loving care to remain serviceable, accurate, and fit for purpose.

Troubleshooting

There are going to be times when an AV system will not work correctly. When this happens, you will need to troubleshoot the systems to find where the problems are located before carrying out repairs or adjustments.

In a high-pressure situation, such as the sudden failure of the AV system during a presentation, conference, or live event, AV professionals are expected to calmly and quickly diagnose the problem and then either fix the problem or apply a workaround until permanent repairs can be made.

As you learned in Chapter 11, troubleshooting is a process for investigating, determining, and settling problems. The most important process in troubleshooting problems is to be systematic and logical. A reliable troubleshooting approach follows a process intended to clearly define the nature of the problem and narrow down the potential issues until the actual cause of the problem is identified. There are three steps involved in troubleshooting:

Preparing to Troubleshoot

Prior to attempting to troubleshoot a system problem, you need to do the following:

Selecting a Strategy

The next step in troubleshooting the problem is to apply the appropriate troubleshooting strategy. Strategies used to identify faults include

Troubleshooting in Live Events

In live event staging, there is often little time to implement a solution when a technical problem occurs. Troubleshooting starts before the gear leaves the warehouse by testing all equipment before dispatch and by determining what spare parts should be carried and which critical systems should be redundant.

On the site, the technical crew has tools, troubleshooting devices, and spare equipment specific to the systems involved. Troubleshooting checkpoints are established in each system for quick location of a signal or equipment failure.

When traveling or touring, a local AV supplier should be secured in advance as backup for equipment and services.

System Maintenance

If your company has been contracted for post-installation maintenance of a system, you may be required to provide ongoing support services. In a maintenance and repair role, your team will be required to maintain, troubleshoot, and repair AV equipment or systems.

Preventive Maintenance

Preventive maintenance is an equipment strategy that is based on inspection, replacement, servicing, or dismantling of AV equipment at a fixed interval, regardless of its condition at the time.

Preventive maintenance may include

Devising a Preventive Maintenance Schedule

The frequency and extent of preventive maintenance activities should be based primarily on the level of use of the installation and the types of equipment installed. Detailed information on the hours of use, and the types of uses, for each section of the installation is necessary to make an accurate estimate of the likely maintenance requirements. If equipment is in constant use, the schedule will require more frequent preventive maintenance, but on the other hand, site visits will probably need to be scheduled outside of normal operational hours to avoid disruptions.

Maintenance Requirements

Before considering the frequency of preventive maintenance activities, it is important to establish which parts of the installation require maintenance. Some devices may sit undisturbed in an equipment rack, suspended from a ceiling, or under a bench, quietly going about their business with no direct user intervention, while others may be moved about the installation several times each day and be connected to by dozens of users, plugging and unplugging a myriad of different personal devices.

Cooling Systems Some devices are designed to operate entirely with passive cooling, relying on heat removal by radiation from heatsinks or by convection through ventilation holes or mesh. Passively cooled devices require regular but infrequent removal of dust and fibers that may accumulate on heatsinks and in ventilation apertures to avoid the device overheating and becoming unreliable.

Devices that are actively cooled with an internal forced air flow require two distinct maintenance interventions: filters and fans. As actively cooled equipment requires higher volumes of air movement than passive convection cooling, this equipment is usually fitted with dust and/or particle filters on the air intake to keep the air flow clean. Depending on the operating environment, these intake filters may require frequent cleaning or replacement to avoid overheating problems. Problematic environments for air intake filters include areas of high pedestrian traffic; food preparation areas with substantial amounts of smoke and/or grease vapors; rooms with chalkboards; places frequented by smokers; and venues such as night clubs, performance spaces, or exhibitions, where atmospheric effects including pyrotechnics, theatrical smoke, fog, and haze are used.

One factor to consider about system cooling health is the change of ambient environment that occurs when a facility is closed down at the end of an operational session. Devices that can comfortably stay within their safe operating temperature range during a normal operational session may find themselves in a space with minimal ventilation and cooling when all the humans pack up and go. If equipment is left after hours in full running mode, or even in warm standby, it may actually place more demand on the cooling system than when in normal operational use, and thus shorten the operational life of equipment.

Moving Parts The other issue with forced-air cooling is the operating life of the fan or impeller devices forcing the air. Together with the phosphor wheels on some solid-state light sources and the color filter wheels on some single-DMD (single-DLP) projectors, these fans and impellers are among the very few moving parts found in most AV systems. Bearing failures on the drive motors may be the most likely point of failure on many pieces of gear, so some research into the estimated operational life of these motors should inform your estimates of service intervals.

Your ears, possibly augmented by an electronic stethoscope, are a very useful tool for assessing the health of motor bearings, as vibrations, whines, and grinding noises can usually be detected some time before the bearings fail completely.

Physical buttons and switches, as distinct from the virtual buttons on GUIs, are another moving part that can fail after repeated use, and checks should be factored into your preventive maintenance regimen.

Limited-Life Components Some components of every AV system have a finite life, and any preventive maintenance regimen should factor the lifespan and replacement procedures for these components into the schedule and the budget.

Projector light sources are a familiar system component that requires regular checks of light output and lamp-hour counters. A preventive maintenance program should be based on the estimated life of the light source and the acceptable decrease in projector output or a specified lamp-hour count that will trigger a lamp replacement before failure.

Some projectors may have solid-state light sources with operational lives that should theoretically exceed the length of an equipment replacement cycle; however, solid-state light sources are particularly temperature sensitive and can fail, or be substantially degraded in either output or operational life, if the cooling system for the light source is compromised.

Batteries are a constant and lifelong maintenance issue with a wide range of AV devices. Although primary cells (single-use batteries) are an operational consumable rather than a maintenance issue, the vast number of portable, rechargeable devices in use is a significant preventive maintenance consideration. A preventive maintenance plan should take into account the entire inventory of rechargeable batteries in everything from wireless microphones, radio talkback units, and handheld radios, to collaboration dongles, handheld video cameras, audience response devices, laptop computers, and, of course, the forgotten army of uninterruptible power supplies (UPSs) lurking in the bottoms of racks and under consoles.

A battery maintenance strategy should take into account the usage hours of each battery-powered device together with the device manufacturer’s specifications for the number of recharge cycles that the fitted batteries should be expected to perform. Batteries and their associated charging systems should be subject to periodic testing for voltages and the condition of the recharging connections on cables, charging stations, and the device’s charging terminals.

UPS batteries are usually replaced at regular intervals based on the battery type and the manufacturer’s documentation, although regular checks of UPS performance, in the controlled absence of an incoming mains supply, ensures that the UPS will indeed supply uninterrupted power when called upon to perform.

Cables and Connectors It is widely acknowledged that the majority of electronic hardware failures are the result of faulty connections. Many of the cables and connectors used in AV systems are rated for only a few thousand (or sometimes even fewer) connect/disconnect cycles, and while this is rarely a significant limitation in a fixed and infrequently changing installation, it can become a critical source of unreliability and failures for systems being constantly moved and reconfigured. A preventive maintenance program should include regular visual inspections and continuity tests on the cables and connectors, on and between equipment subject to frequent connect/disconnect cycles, and the potential for physical mishandling.

Software and Firmware Device firmware, operating systems, and AV system software are frequently updated—sometimes to add extra capabilities to devices and systems, but more often to remedy bugs and other issues that have arisen since the previous version was released. If a preventive maintenance schedule is to include the acquisition and installation of bug fixes, updates, and upgrades, it is important to establish guidelines for what type of updates are to be undertaken on each device in the system. Clients may prefer to leave some system elements in their current “if it ain’t broke, don’t fix it” state or may choose to keep elements up to date with the latest features, bug fixes, and security patches. It is not uncommon for clients to opt for stability and security with some critical systems, while wanting all the latest bells and whistles installed on others.

A preventive maintenance program may include periodic equipment shutdowns and restarts for systems that are otherwise left in continuous operation.

Fallback and Failover Systems AV systems may include redundant duplicate (or even triplicate) components to provide fallback and failover contingencies for critical operations. A preventive maintenance program may include checking and testing the offline redundant devices and simulating, or deliberately creating, a controlled fault event that will verify the functioning of both the changeover system and the redundant equipment. The program may also include provision for rotating or exchanging the active and standby devices.

Creating a Maintenance Log

A maintenance log is essential on fixed installations. It should include every item examined and repaired and the service performed. Maintenance logs are easy to update, especially right after service has been performed.

Table 17-1 shows the types of data recorded, including the date and time the system was checked, who checked it, and the status of the system. It also includes problems that were discovered and what measures were taken to fix them. You should make it standard practice to record corrective measures that were taken to restore system performance or recommended actions and whether they are acted upon or not. From time to time equipment may need to be updated. For example, in a boardroom, a digital media player may replace a Blu-ray player. The date this took place should be documented, as well as how the signal was rerouted.

Table 17-1 Type of Information in a Maintenance Log

As you may have noticed in Table 17-1, the installers established a good relationship with their client, which opened the door for repeat business and referrals. When you do a great job installing a system, the client may choose to contract with your company to provide long-term maintenance on the equipment.

Maintaining Your Tools

Keeping your installation, maintenance, test, and alignment equipment in safe working order is an essential process that underlies every aspect of AV technical activity. Every task you undertake requires that not only is every tool up to the task you require of it but that it will also be safe to use.

Staying Sharp

Many of your tools, from drill bits to jigsaws, from cable cutters to utility knives, and from wire strippers to angle grinders, require sharp and correctly aligned cutting edges to function effectively and safely. Some of these tools require regular sharpening and alignment, while others can be kept ready for use with replaceable cutting blades or discs. If a tool is losing its edge and underperforming, it is time to consider whether the tool is being used for tasks beyond its intended capabilities or whether it has simply become worn from use. Whichever is the case, the cutting capability should be restored by either resharpening and realignment or by replacing the disposable cutting edge. Not only does having a fully functional tool improve your efficiency at a task, but it also decreases the risk of the tool jumping or skipping in operation and putting you at risk of an injury.

It is your responsibility to have adequate tool replacement parts available to complete your tasks, to have an understanding of the processes required to acquire additional replacement parts, and to have tools resharpened, realigned, or replaced.

Staying Safe

No AV project, however critical or spectacular, is worth dying for. An important part of every project is to complete it to the highest possible standard—and then go home safely. There are a vast number of potentially dangerous tasks in every occupation, but acknowledging those risks and taking all the necessary steps to avoid dangerous outcomes is an important skill.

The requirement for the safe use of appropriate personal protective equipment (PPE) is discussed in Chapter 5 and mentioned in other sections where specific risks and safety practices are important. The use of the appropriate protective and safety practices should be an integral part of all work activities.

Preparation of your tools for each task should include checks for tool safety before each use. Visual checks of the condition of the tools should include verification that all safety guards are in place and operational, that all parts are present and undamaged, and that electrical supply plugs and cables are correctly terminated and in a safe condition.

Although many powered tools are driven by internal, low-voltage, rechargeable batteries that pose no electrical hazard, there are a substantial number of devices that require a mains supply for operation. It is good practice to inspect, and if indicated, test the wiring and insulation on mains-powered equipment before every use.

Many jurisdictions require regular inspection and testing of all mains-powered devices on a work site, including cables and distribution equipment. Most also require that labels be attached to the equipment to record when it was last tested and that records be maintained to track the safety history of each device. Building construction sites are often subjected to very stringent safety practices due to the high risks associated with building activities. Some jurisdictions categorize live event production as a construction activity from a safety perspective.

Staying Accurate

An AV installation and maintenance toolkit includes many devices used to measure, test, and align systems and equipment. These tools may include everything from a simple multimeter to sophisticated signal generators, from basic cable continuity testers to time domain reflectometers, and from light meters to color alignment systems. What they have in common is their capacity to provide a measurement or a standard signal that can be used to assess whether a device or system is functioning within the required parameters.

To provide a useful signal or measurement, the accuracy of the device must be known. The accuracy of the multimeter you use for basic continuity or pin-out testing on a microphone cable or a loudspeaker line is probably not important so long as the meter goes “beep” or lights up as an indication of low resistance. But if that multimeter is being used to check the voltage of a power supply or measure the voltage drop on a cable run, accuracy may become critical. The accuracy of the signal patterns produced by test signal generators are critical for the correct alignment of entire chains of AV equipment, so it is important that these signals are within the acceptable tolerances for their alignment and measurement tasks. The value of most test instruments is in their capacity to provide repeatable and accurate values.

Most test and measurement equipment is initially supplied with some documentation of its accuracy, reference information on the range of values that it can output or measure, and the range of operating conditions under which this accuracy can be expected. Professional-quality equipment will come with some form of certification of its calibration and an indication of how frequently it should be recalibrated.

Recalibration of test and measurement equipment is a complex and highly specialized procedure, usually undertaken by nationally or internationally accredited testing facilities. The calibration process involves the equipment being tested against certified standards for voltage, temperature, intensity, frequency, radiation, pressure, etc., and adjusted for an accurate response. Not only is such calibration quite expensive, it is rarely a fast process, meaning that equipment can be out of service for appreciable periods while it is being recalibrated.

While it is important to have all AV test equipment maintained in a state of accurate calibration, it is not usually necessary for every piece of equipment to be calibrated to laboratory accuracy. By regularly maintaining calibration of a single, high-accuracy device to laboratory standards, an organization can then use that device as a local master reference to check the accuracy of other equipment, either by directly comparing measurements against the reference device or by creating a local set of known standard values (resistances, voltages, signal patterns, etc.) to be used for calibration.

It is wise to consider which test and measurement equipment needs to be frequently and accurately calibrated for specific tasks. A multimeter that is reading low by 100 millivolts will usually not be a problem when checking if a power supply is producing an output, but a 100-millivolt discrepancy in a video test signal can be significant.

Chapter Review

In this chapter you studied the tasks involved in troubleshooting and maintaining AV installations and maintaining your tools and test equipment.

Upon completion of this chapter, you should be able to do the following:

This book provides a comprehensive study of the knowledge and skills listed in the CTS-I Exam Content Outline. This is a good time to try yourself out on the CTS-I online sample questions (see Appendix E), even if you have attempted them earlier.

Review Questions

The following questions are based on the content covered in this chapter and are intended to help reinforce the knowledge you have assimilated. These questions are similar to the questions presented on the CTS-I exam. See Appendix E for more information on how to access the free online sample questions.

Answers