To get the most mileage out of gear, regular equipment inspections and Preventative Maintenance (a.k.a., PM) are a must. Many of us (unfortunately) have additional downtime at present, but it does provide the opportunity to take on this necessary chore.
All equipment in your inventory should have PM scheduled at least once a year, and more frequently if it goes out the shop door a lot and/or is exposed to harsh environments. PM comes down to inspecting, testing, cleaning, lubricating and repairing to keep systems in top operating condition.
In addition to annual PM, all gear should be given a quick inspection during setup and tear down at every gig. This includes a visual inspection, placing a hand on equipment to feel operating temperature, tugging on cable ends to see if strain relief is in good shape, etc.
If irregularities are noted, further inspection should be performed and problems addressed. Not paying attention to small problems allows them to build up to big problems that are much more expensive to correct, and they can also result in a failed gig. Here I’ll share some of the PM approaches I regularly utilize with my own gear.
PM for electrical gear like processors, amplifiers, and snake boxes always starts with a complete visual examination. Each unit’s case is opened up for visual inspection of the interior. I’m looking for loose or broken wires, unseated connectors, blown fuses, discolored circuit boards, and so on.
While the case is open, it’s a great opportunity to run a vacuum and clean out all dust and road gunk that has accumulated inside. Sometimes an air compressor, or at least some “canned air,” is used to blow out the dirt. I also remove filters and clean or replace them per the manufacturer’s instructions.
Next up is checking and cleaning signal connections. If the equipment has faders and knobs, it’s time for cleaning and lubrication (again, per the manufacturer’s recommendations).
All electrical pins and connection surfaces are evaluated for corrosion and misalignment, and input and output connectors are given a thorough cleaning with an electronic cleaner such as Deoxit from Caig Labs. If connectors need to be repaired or replaced, this is the time to do it.
With the case still open, it’s a good ideal to double check all power cable connections, and if the unit has a fixed power cord, to make sure the strain relief is in good shape and the cord has no cuts or tears in the outer jacket. I also run my hand down the cable to feel for internal cable damage. If the unit takes batteries, they get a check, and the battery terminals are cleaned.
Before plugging in and powering anything, I make sure all cleaning fluids or solvents have dried. After a quick check to make sure the equipment is operating correctly, each component is sealed back within its case.
Rack-mount gear is a little harder to access without removing from the rack, but I strongly believe that doing maintenance is so important it’s worth the trouble. Note, however, that opening up some gear may void the factory warranty, so please read and follow all manufacturer instructions on maintenance.
Modern microphones are pretty robust and usually don’t require a lot of attention, but they should be inspected after each use because they’re regularly dropped, exposed to liquids, etc.
Because the majority of my jobs are corporate gigs, which are usually relatively tame, I only do serious mic maintenance once a year.
But for those doing outdoor festivals and/or working with much more “raucous” forms of entertainment, there could be need to do maintenance as often as every month.
Many models allow you to remove a damaged grille/head to simply screw on a new one. Factory replacement heads are usually available, and a few companies also make generic heads that fit popular microphone models.
And sometimes they can be fixed. For round ball-shaped grills, the handle of a large screwdriver can be used to gently pressure out dents. If a dent is a little stubborn, I place the ball on top of a folded towel and tap the screwdriver with a small wooden mallet.
Before grilles are re-attached, they should be cleaned with a mix of dish soap and warm water, with a soft bristled toothbrush to help scrub out the dirt. Some folks use Listerine for cleaning, and there’s a foam-based cleaner called Microphome available as well.
Inner foam windscreens can be replaced or washed in a mix of dish soap and warm water. These should be wrung out and air dried completely before being reinstalled. For mics that don’t have removable grills, I use a dry soft bristled brush on the exterior of the grille to remove dirt and then hold the mic upside down to help loose dirt and debris fall away.
Don’t leave batteries inside mics between shows because they can leak and corrode the contacts and generally ruin the electronics. To keep these terminals (as well as mic connectors) clean, I use Deoxit, then wipe them dry with a clean cloth.
Don’t forget the clips! Mic clips should be checked for signs of cracks and missing pieces. Also evaluate the threads and the tightness of the swivel. I normally place a drop of light lubricating oil or WD40 on the threads so they’ll screw easier on to mic stands.
Safety is more important than looks or sound, so the first thing I check on loudspeaker cabinets is the rigging, making sure nothing is cracked, bent or distorted. All moving parts should be cleaned and lubricated per the manufacturer’s recommendations. Also don’t forget to keep an eye on external hardware like handles, corners and grilles, fixing anything that requires attention.
Connectors (and their panels) should always get attention as well, to make sure they’re intact and secure. For powered loudspeakers, give the power cord and amplifier a check before testing out the box.
During down times, I power up boxes and run a sweep tone through them to insure that drivers and crossover (if applicable) are O.K. For subwoofers, I usually run a kick drum sound from a drum machine as a general test, in addition to evaluating frequency tones.