Radio troubleshooting: Hardware & software

I have a theory about troubleshooting radio gear or, for that matter, any type of electronics. Troubleshooting involves the use of hardware and software. I don’t mean computer software and hardware — although these items have become an integral part of land-mobile radio servicing. The software to which I refer is the old gray brain matter. The hardware comprises multimeters, wattmeters, service monitors and all other such equipment, including simple hand tools.

Someone in the land-mobile radio business once said that a proficient troubleshooter can fix more problems with a few simple devices than a less-proficient technician can with a multitude of the finest test equipment. A highly proficient radiotech (an adaptation of “radioman,” but without gender) can fix more stuff in a day (read: Earn more money for the shop) with a multimeter, a soldering iron, a screwdriver and a pair of pliers than a radiotech “wannabe” of less ability can with an array of test equipment including a communications analyzer, a spectrum analyzer and everything in between.

The difference lies in the software. The ability to troubleshoot is a gift. If someone has no innate ability to troubleshoot, then no amount of training will make that person a real troubleshooter. It has to do with mentality (not to be confused with IQ). It’s a state of mind. Some people just have an ability to analyze data and information and come up with a logical conclusion based on an analysis of that collected data and information. Not everyone has this ability, and (in my opinion) it can’t be taught. You either have it or you don’t.

So, does that mean that we should abandon training? Absolutely not. Radiotechs who have this innate ability to analyze data to troubleshoot electronic equipment still require training. The difference between a good land-mobile radio troubleshooter and a great radiotech is training. Knowledge of the equipment and operating principles used to analyze equipment malfunctions is acquired through training. Unless the radiotech knows how the equipment is supposed to normally function, it will be difficult to apply logical troubleshooting analysis to that equipment when it malfunctions.

Test & measurement procedures

All radiotechs must perform certain test-and-measurement procedures to understand the operation of the particular piece of equipment being analyzed. Many test-and-measurement procedures have been developed and standardized over the years by various organizations, including the American National Standards Institute, the Electronic Industries Association, the Telecommunications Industry Association, the National Institute of Justice, the Institute of Electrical and Electronics Engineers and others.

Of greatest importance to land-mobile radiotechs is TIA/EIA document 603-1. It includes all standardized test-and-measurement procedures that are pertinent to the performance testing of land-mobile radio equipment. This document (well, book, actually; it’s nearly 300 pages) is available by writing to: Global Engineering Documents, 15 Inverness Way East, Englewood, CO, 80112-5704, or by calling: 1-800-854-7179. The Web site address is www.global.ihs.com.

Specifications that are found in land-mobile radio equipment technical manuals are based on this document. To ensure that equipment meets or exceeds the published specifications, certain test-and-measurement procedures must be performed on that equipment. These test-and-measurement procedures must conform to the standard procedures laid out in documents such as TIA/EIA 603-1.

Standard procedures exist for measuring receiver sensitivity and selectivity, transmitter power output and frequency, spurious output and all other pertinent criteria associated with radio performance.

In general troubleshooting, it isn’t always necessary to follow the standard test procedure for a particular test or measurement. But when you want to compare the result to the published specification, make sure that you follow the standard procedure to the letter. We want to compare apples to apples and not apples to oranges.

Getting back to the theory of a radiotech, it may not be possible (even with intensive training) to make a proficient troubleshooter out of just anyone who comes along. But training can turn a fair or good troubleshooter into a better one. Also, a good troubleshooter might get the job done with minimal test equipment, but imagine what that same radiotech can do with great test equipment.

A good radiotech approaches a job with an open mind, a knowledge of the equipment and the necessary test devices in hand. Never decide what is wrong with the equipment and then set out to prove your theory before you arrive on site. Let your test procedures guide you, logically, to the problem. You must have confidence in your equipment and in your test procedures — otherwise the time and effort is wasted. Divide and conquer is a fundamental principle of troubleshooting. If your test-and-measurement procedure(s) lead you in a different direction, don’t be reluctant to move in that direction.

As a young troubleshooter, I was working with a mobile radio on the bench. All test-and-measurement procedures indicated that a particular capacitor was defective. It was in a nearly inaccessible location on the board, and it looked like a new one, anyway. So, I wasted time trying to prove that the trouble wasn’t the capacitor. Yet, all logical test procedures still led to the same capacitor. Finally, just to prove that the capacitor wasn’t bad, I removed it from the board to test it out-of-circuit. Of course, it was leaky. Replacing that capacitor cured the trouble. The extra time spent wasn’t a total waste, though, because I learned from that experience.

The angle of attack has evolved over the years from troubleshooting down to the component level to troubleshooting down to the board. Now, we seem to be more involved with system troubleshooting. Whatever type of troubleshooting you do, the basic principles remain the same. Approach each job with an open mind, and let your test-and-measurement procedures be your guide. Anyone can replace a bad part to fix a broken radio, but it takes a real radiotech to find which part is bad.

Until next time — stay tuned!

Contributing editor Kinley, MRT’s technical consultant and a certified electronics technician, is regional communications manager, South Carolina Forestry Commission, Spartanburg, SC. He is the author of Standard Radio Communications Manual, with Instrumentation and Testing Techniques, which is available for direct purchase. Write to 204 Tanglewylde Drive, Spartanburg, SC 29301. Kinley’s email address is [email protected].