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SM Transmitter Cleaning – Tips for Battery Doors and 5-Pin Jacks

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SM transmitters might go through hell on the job --  but they don’t have to look like it.  Battery doors and the 5-pin jacks are particularly susceptible to wear and tear. These tips can help:

Battery Doors

IMG 3410If the battery door and mating surface on your SM series transmitter look like this and are starting to become difficult to open, don’t scrub them with an abrasive!  We’ve seen a few units that were damaged by steel wool, sandpaper and other materials. Multiple problems can be created as a result, such as getting particulate (tiny pieces that break off) into the unit, damaging the battery contacts on the door, and removing the conductive coating from this area and even the entire housing. 

IMG 3411To clean, we recommend Wright’s Silver Cream (available in Walmart and Home Depot; under $10 for a small container that will last you a year or more) to clean the door and housing. 

Using a small amount of cream, allow to dry and then GENTLY clean the cream from the door and housing. If excessive force is used when removing the dried cream, the conductive finish can be removed along with it.

Removing the thumbscrew from the door can make cleaning easier, though it should be done in a specific manner. Instructions on how to properly do that can be found here. Please keep an eye on the e-clip and washer which, if either are lost, damaged or replaced incorrectly,  can cause the thumbscrew to not seat properly in the case and cause wear to both the door and mating surface.

Your end result after cleaning with the cream will look like this:

IMG 3412

The 5 Pin Microphone Jack Opening

The 5 pin opening and contacts for microphones on SMs can likewise collect grease and dirt. You might think that an easy fix for this would be to use a contact cleaner such as WD-40, Goo Gone or acetone, but there are two potential problems with this idea:

  1. Any type of liquid can seep into the unit under surface mount parts and thru-holes and build up on the circuit boards. We don’t want to tell you how many units we have gotten in due to this type of “cleaning”…or how many of those transmitters ended up being a lost cause.
  2. The labeling on many contact cleaners will read something like “compatible with most plastics, paints and rubber surfaces.” The problem is that the labeling is not specific enough. Which plastics, paints or rubber surfaces? Theoretically, you could clean the battery contact and the 5-pin, but there is nothing keeping the liquid out of the unit.

So how do you clean the 5-pin jack?

First, you can try canned air. You probably have some lying around (if not, it’s inexpensive) and it will blow out any dust or lint-like particles inside. If that doesn’t work, you can do what we do here.  We clean it using alcohol and an acid brush (used to apply paste flux for soldering; cost under a dollar and available in any hardware or home improvement store, often in multi-packs), while holding the unit upside down to keep the contaminants out of the transmitter.

Alcohol and brush  Cleaning with the brush 

All of these suggestions will can go a long way in ensuring that they not only work well and stay out of Repair, but look like new, longer. 


Lessons On Battery Care For The Long Ranger

Social Media WireLists3The Long Ranger Wireless PA has been in the field for over 30 years and remains popular with school marching bands. Every fall after summer break, and again after winter break, like clockwork, we see a fleet of Long Rangers coming in for service with easily-preventable battery-related issues. And in case you were wondering, premature battery failure is not covered by warranty. Here are five things to consider to make sure that your Long Ranger is ready for another semester:

  1. At the end of each use and especially before extended breaks, store your Long Ranger in a safe, dry place that is ideally under 77°F. At 77°F, Long Ranger batteries are estimated to last about 5 years (3 years with the Long Ranger IV) with regular charges. For every 15°F rise in temperature, battery lifespan is cut by 50%. We know that some of you live in warmer climates; our temperature suggestions do not apply to operating environment.
  2. As a best practice, charge the batteries before putting the unit away; and again every 30 days if left unused.
  3. Never allow the batteries to completely run down. This is the best way to ensure long battery life and prevent premature failure. The 12-volt lead-acid battery should last for 6-8 hours during normal-use conditions.
  4. If the batteries have completely run down, don’t give up right away - they may be able to be saved. In the LRIV, an almost-new 12-volt battery that appears to be “dead” can possibly be saved by prolonged charging – up to ten days. And don’t worry, all Lectrosonics equipment contains circuitry that prevents over-charging.
  5. If you decide to change the battery in your Long Ranger, refer to Tech Note 1012 ( or Tech Note 1021 ( depending on which battery you currently have installed. We no longer use the individual 6-volt batteries at the factory, however you may be able to source them locally. To convert the battery from two 6v to one 12v, you should refer to Service Note 1001 ( These Tech Notes cover important removal and replacement tips. For example, a battery pack connected backwards will result in costly damage. During factory service on all Longer Ranger models, a new 12-volt battery is included with your repair fee.


My Transmitter Doesn’t Work! Three Things To Check

Social Media WireLists2One of the most common calls that we get in Customer Service is that a transmitter “doesn’t work.” Since “doesn’t work” is a very broad complaint, there are four things that you should check, prior to calling us, that could help you self-troubleshoot and possibly eliminate the need for a call altogether:

  1. Do your transmitter and receiver both have power? While it sounds rudimentary, ensure that your units are plugged in or that your batteries are fresh. Bad or weak batteries are surprisingly common. A general rule is to store your units between use without batteries, and supply new or freshly charged batteries at the start of each session. And make sure your batteries are inserted correctly – it’s easy to put them in the wrong way. All of our units are marked with battery orientation somewhere – either on the back or side of the unit, or inside the battery compartment. You may also need check your power supply, battery eliminator or BDS unit for proper voltages.
  2. Are your transmitter and receiver on the same block and are they tuned to the same frequency? These two discrepancies account for a great number of the calls that we receive. Additionally, if you’re trying to synch a transmitter and a receiver in the 486.400 – 495.600 MHz range of Band A1 and things are not working, it’s possible that you are running into the Block 470/19 overlap. For things to work in this situation and enable the correct pilot tone, your block and hex codes must match. Because of the unique design of the Lectrosonics products, each frequency within a block has a different pilot tone. This helps prevent unwanted un-squelching when an intermod lands on a receiver channel. However, the overlap between blocks 470 and 19 within the A1 band means you can have the correct frequency but since the transmitter and receivers are set to different blocks, the pilot tones don’t match. Be sure to check both the frequency AND the block if you are in Band A1 but are not getting audio.
  3. Are your transmitter and receiver on the same compatibility mode? Like frequency and block, if two different modes are selected, the units will be unable to communicate, or you may have audio distortion. Like people speaking languages, they both need to be using the same one in order to understand each other.

We hope that your issues are solved with one of these four checks. If not? Give us a call at 800-821-1121. We’re here Monday to Friday, 8 to 5 Mountain Time.

-The Lectrosonics Parts & Repair Team

The 4 Don’ts for Preventing Sick Transmitters

Corroded board

Nothing is more frustrating than turning on your transmitter…and…finding out it doesn’t work. Like with winter colds, sick transmitters can take some diagnostics to figure out and cure. Here are 4 suggestions to help prevent problems before they start:

1. Don’t place the transmitter against bare skin. All transmitters are susceptible to becoming damaged from moisture, including sweat (and everyone sweats). Sweat is a carrier for water, salt and oils which can leech into the transmitter and corrode the circuit boards and other parts. Once sweat or other moisture seeps inside the unit, there is no wiping or removing it. So how do you prevent this? By placing the transmitter into a pocket, pouch or baggie; or (best option) using one of our specially-designed silicone covers. Pro tip: keeping transmitters – and especially their antennas – away from skin also improves RF transmission, bodies are mostly water and water absorbs RF.

2. Don’t leave batteries in an unused transmitter. Best practice is to remove them when you are done with a project or a job and replace them with fresh ones when the unit is used again. At best, batteries that are not powered up can lose charge over time. At worst, they can corrode or leak, thereby irreparably damaging your unit. In general, we recommend that you use fresh batteries for each job, performance, sermon or gig. Because our units provide very high-performance RF and audio, they do use a fair amount of current. New or freshly charged batteries are part of the formula for success.

3. Don’t wrap cords or mic cables around your transmitter when it is not being used. Over time, this practice will damage the cord. Mic cords cannot be repaired or replaced if damaged. Disengage the mic and wrap it loosely to prevent pinching or kinks. Most lav mic manufacturers provide a pouch or small plastic box for storage. If yours didn’t come with anything, we sell our MICBOX (sold with our lav mics) and our small zippered pouch, part #35939 (sold with the HM172 headset microphone) separately, for a reasonable cost.

Corroded housing4. Don’t trust the repairs! We don’t mean this literally, of course! When a unit is repaired and returned to you, immediately power it up and test it. Ensure that it works properly before storing it. Each unit that we repair has a 90-day warranty on the repairs. We need to know sooner rather than later that the repair wasn’t adequate, so we can then correct it under warranty. Sometimes, we learn that users have received a unit back from repair, then stored it for months until the next time they need to do a job, when they discover that it doesn’t work properly. This is rare, but it does happen.

Our products have reputations for withstanding heavy demands over a long lifetime, and the care you give them goes a long way in keeping them in peak performance.

- The Lectrosonics Service & Repair Team