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Veejar Enterprises - Garland, Texas

 

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Part 5  More On Electronics 

Welcome to all those who have recently signed up for our 

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Part 5 - What's All The Talk About Electronics?

What do I need to know? What do I need to do?

 

Back in Part 3 we asked these questions and some insight. In Part 5 we will answer the first two questions with more specifics.

   

What do I need to know about electronics now that computers are involved?

What level of training do I need in electronics? 

 

By the way, stay connected to our email newsletter list. We will very soon announce by email a new web site where vehicle service technicians can access our 60 lesson training program called "The" Vehicle Electronics Training Program for on-line study.

 

For now, let's discuss what technicians should do about vehicle electronics training in today's vehicle industry. We have seen dramatic changes in electronics in just the last two decades. One area specifically is construction of PCBs (printed circuit boards). Electronic components have become more miniaturized than ever before allowing complex electronic circuits to be created in smaller packages. This makes circuit boards much smaller and less expensive to produce, but practically impossible to repair by human hands. They are simply too small. Although very advanced PCBs are very difficult to repair, they have created a revolution in electronics training.

 

Here are some examples of what I'm talking about. The first illustration in Figure 1 shows the electronic component size found in vehicle on-board control units in the late 1980's compared to a 10 cent dime.

Fig. 1

Electronics components mounted on an old style PCB 

   

Notice the size of the fixed carbon resistors, they are the components mounted vertically with painted color bands indicating their resistance value. The light orange disc capacitors with two leads lying flat at the top right, the other two mounted vertically compared to a dime are easy to replace by hand if needed. There are two integrated circuits large enough to be de-soldered and a new IC installed, if needed. It is also possible to measure the voltage or the waveform with the lab scope on any of the pins of an IC that are physically this large.

 

The size of these components are quite easy to handle by human hands and a needle nose pliers. The components can be inserted into the circuit board and soldered in place with little trouble and average eyesight. Also consider how large the size of the circuit board and how heavy it would be containing a complete circuit consisting of several ICs, power transistors, multiple resistors and capacitors.

 


Fig. 2
Power Transistor mounted on a PCB

 

   

 The power transistor is almost as large as a dime. An electronic technician would be trained in electronics school to test the transistor with the proper type of ohmmeter and look for a bad internal transistor junction. He would also be trained in an electronic school to measure the voltages and waveforms on the appropriate transistor leads.

 

If the transistor is found to be defective, the three transistor leads can easily be de-soldered from the circuit board. Remove the mounting screw, de-solder the three leads, remove the transistor, insert a new transistor, install the mounting screw, and re-solder the three leads. This would be a simple task for an electronics technician with a soldering iron and needle nose pliers. This was common PCB repair in the old days.  Printed circuit board technology has come a long way in the last 25 years.  

 

In Figure 3 below, we see a photograph of a modern day computer printed circuit board. Notice the small size compared to the size of a 10 cent dime and the rows of tiny "chip" resistors and other circuit components.  

 

 

Fig. 3
Small electronic component size compared to a 10 cent coin
 

 

Measuring voltage and waveforms at the smaller IC pins is more tedious than before. The probe tip could easily short two pins together and possibly destroy an IC.It has reached the point where the circuit boards contain miniature components that are almost impossible for a human to replace. I can tell you from personal experience trying to repair these new circuit boards with "chip" components when they first began to arrive in vehicles in the late 1980's, was a nerve racking experience. Trying to replace one of those tiny "chip" components and solder it at both ends while holding it in place with a needle nose pliers took patience and skill. It did not take long for manufacturers to realize these tiny "chip" components could not be replaced by human hands.

 

As a result of this change in electronic component size and PCB construction, the training required of technicians to repair circuit boards began to decline. Vehicle manufacturers decided to replace defective control units with new ones rather than have them repaired by electronics technicians. Today, most onboard computers, due to this new PCB technology, are replaced rather than repaired. This also affects other segments of the electronics industry. One example, if your home/office PC develops a problem on the motherboard, it is more economical to buy a new motherboard rather than attempt to repair the old motherboard.

 

Therefore, schools that taught electronics for circuit board repair down to the component level began closing down due to low student enrollment. There is a declining need for electronic technicians with skills to repair circuit boards in today's technology. As a result, many of the electrical and electronic troubleshooting skills that were taught in electronic schools in the past is being lost. They are not being passed on to the next generation. Some of these skills would be helpful for a vehicle service technician to test a vehicle electronic system.

 

For example, the technique of testing a transistor with an ohmmeter is being lost. Of course, a service technician today would never be expected to test and replace a transistor in an onboard computer. But knowing how to test solid-state components like transistors and diodes with an ohmmeter can be adapted in other areas of vehicle maintenance. This skill could be used to test L.E.D. lamp assemblies and some sensors containing solid-state components. I could cite several examples but due to the length of this article I only want to address one.

 

A few months ago I was conducting an electrical - electronics training class in a fleet maintenance shop. The technicians in the class mentioned they were having trouble with an emergency flashing light unit mounted on many of their vehicles. Some vehicles would have two or four of these units mounted on the vehicle. They would last about six months then they would have to be replaced at almost $200 a pop. We disassembled one of the defective units and on the circuit board was a power transistor. I tested it with my ohmmeter and saw that it was bad. It would have been a simple task to de-solder the defective power transistor and install a new one to repair the unit. The cost to repair by replacing the power transistor would have been less than $20 and taken 10-15 minutes.

 

Let me say this loud and clear. I do not recommend, nor do I imply a vehicle service technician ever open up an on-board computer and attempt to repair the circuit board. These emergency light assemblies with solid-state components are a different matter and perfectly safe to look inside and repair. But NEVER do that with an on-board vehicle computer. 

 

Today it is more economical to replace an on-board control unit rather than train and pay an electronics technician, provide an expensive electronic repair workstation to repair the original circuit board when it develops a problem. It is cheaper in most cases to build new on-board control units rather than repair old ones. So many manufacturers ask why continue to train electronic technicians to repair computer circuit boards down to the component level when a brand-new unit can be manufactured at less expense?

 

I think we can all agree with that decision, but let's not overlook the need for the proper electrical - electronics training to help a service technician make the decision that the problem is inside the computer or something in the vehicle circuit has caused the computer failure. Let's eliminate the guessing game that the on-board computer is bad or the problem is in the vehicle circuit.

 

What do I need to know about electronics now that vehicle computers are involved?

Today's vehicle electronic technician does not have to study in depth electronics theory to be able to repair computer circuit boards. For example an electronics technician is taught to calculate the inductive reactance in ohms of a coil in a circuit at a specific frequency. He is taught to calculate the capacitive reactance of a capacitor in ohms in a circuit at a specific frequency. Neither exercise would be of benefit to a vehicle service technician. So we can dispense with this in-depth level of electronic training for a vehicle service technician. What is really needed is a training program that specifically addresses the skills to handle the electronics level of diagnosis and repair the vehicle service technician faces with today's vehicle technology.

 

What level of training do I need in electronics?

A vehicle service technician does not have to become an electronics technician but should have a clear understanding of the principles of series and parallel circuits. How circuits work, how circuits fail and how to electrically troubleshoot any circuit on any vehicle should be the main focus of hands-on training. A vehicle service technician should understand the DMM and Current Clamp, not just in theory, but in practical application from effective hands-on troubleshooting training exercises.

 

He should understand technical subjects such as the workings of a coil in a DC circuit and what parameters he should be concerned with if the coil is controlled by an expensive on-board computer, such as spike voltage protection. He should understand the importance of capacitors in DC circuits. This would be beneficial to vehicle service technicians dealing with hybrid vehicles employing "ultra-capacitors."

   

This is the ultimate goal of electrical electronics troubleshooting training for vehicle service technicians. The training should encompass hands-on troubleshooting techniques that allow a technician to perform circuit tests to reveal circuit problems even when service information is not available and the technician has little or no previous knowledge of the circuit. This may sound like a tall order but this level of electrical-electronics troubleshooting training is available right now.

 

Visit our web site for all the details about our electrical-electronics training programs that address these issues and more. These three links will help you navigate our main website.

 

If you are a service technician click here.

 

If you are a shop owner click here.

 

If you are a teacher click here.

 

These links will explain our various training programs and give you direction on how to proceed.

 

If you are interested in the 60 lessons and would like more information about
"The" Vehicle Electronics Training Program click here.

 

Stay connected to our email newsletter list. We will very soon announce by email a new web site where vehicle service technicians can access our 60 lesson training program called "The" Vehicle Electronics Training Program for on-line study.

 

Technicians will study the lessons online and print out their own lessons if they wish. We will be offering a lifetime membership to this website. We also are planning some exciting additions to the 60 lesson home study course that will also be provided over time. We will let you know as soon as this website is posted on the Internet and ready for enrollment.

 

The next installment, Part 6, we will answer some of the following questions.

How do I test a driver transistor circuit?

What is required testing a vehicle computer?

If the circuit doesn't work, how do I tell what is the reason for the failure?

Is the problem in the computer or a problem in the vehicle circuit?

Can a computer circuit fail because there is a problem in the vehicle that will cause the new computer to fail after I replace it?

What do I need to do to increase my electronics knowledge without over kill?

How much electronics training is enough?

Look for our special announcement.

 

 Vince Fischelli  

Director of Training

Veejer Enterprises

Web site: www.veejer.com

Email: vince@veejer.com  

Phone: 972.276.9642

Fax:  972.276.8122 

 

 

 
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Posted: Mar 29, 2016,
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