Bill of Materials

The bill of materials (BOM) associated with a PCB provides a complete listing of the components present on that board, as well as possible optional ones depending on the PCB revision and configuration. It would be great to have the BOM readily available as it definitely cuts down the amount of work to create one yourself, and eliminates guess work and further effort to determine the values of components such as resistors, capacitors, and other surface-mounted devices (SMDs) which are too small to be marked.

On top of that, most military-grade PCBs have one peculiarity—the ICs used are of military specification (MIL-spec) type that do not exhibit the familiar standard industrial part numbers (e.g. SN74LS00), but have cryptic and hard to decipher NATO or national stock numbers (NSN), or MIL-STD-883 part numbers (e.g. M38510/30001).

To create a BOM for the PCB, you need not go into details the way the manufacturers do for their products. It's meant to be for your reference so keep it simple with just the two essentials—part number and reference designation. Below is a sample BOM which I made from a military PCB:

Notice the MIL-STD-833 part numbers for most of the ICs ending in /833 or /833B? Even the discrete components are MIL-spec grade! The values of the resistors can actually be determined from their part numbers, but the capacitors will need referencing to the manufacturer's look-up tables based on their groupings (i.e. M39003/01, /03 and M39014/01, /02).

Identifying the components on a PCB, however, will require some knowledge and familiarity about their appearances and takes a bit of practice.

Assessibility

Generally, PCBs can be grouped into four types: through-hole, surface-mounted, mixed, and flex-print. Prior to the appearance of ball-grid-array (BGA) components, majority of the PCBs have little or no accessibility issues since the component leads or pins are visibly soldered to the board by machine or by hand. There are exceptions, however, when a manufacturer decides to apply some kind of epoxy compound over certain parts of the PCB to provide support for weak spots or socketed components, or simply to mask off sensitive information to keep prying eyes away or discourage repair and rework.

SMT technology has, however, evolved to the point where even more precious board space savings can be achieved on the PCB, by transforming the through-hole pin-grid-array (PGA) a step further to the surface-mount BGA. Such progress is seen as inevitable and necessary in engineering expediency and business sense, but not necessarily appreciated and welcomed by the test and repair communities, since it severely hampered the ability to test and repair this type of PCBs using traditional methods and equipment.

The often hyped alternative solution to this predicament is boundary-scan or JTAG testing. Granted, many new ICs including the BGA types have in-built JTAG circuitries, but ensuring that a PCB meets the JTAG requirement will take additional efforts on the designer's part to implement to realize the design-for-testability (DFT) goal.

Accessibility of probe points is thus an important factor to consider before reverse engineering work can commence. You should therefore make an estimate of how much of the PCB's component leads or pins are accessible, compared to those that have been obstructed, hidden, or even buried intentionally. One other factor that adds to the problem of accessibility is conformal coating; we will look at it separately since it's quite a broad subject in its own right.

Basic Preparation Work

"If you know both yourself and your enemy, you can win numerous (literally, a hundred) battles without jeopardy."

Sun Tze, The Art of War, c. 544-496 BC

The same is true when it comes to reverse engineering a PCB. I have mentioned previously the background that is expected of you—that's knowing your abilities and the areas you may be lacking for a start. Not that you can't start right away. It'll be good though to make an inventory list of the areas you need to brush up and get back up to speed, and where you really need to put in effort to build up that knowledge.

As for knowing your enemy—well, that's what Chapter 2 is all about!

Getting to Know Your PCB

I don't know about you, but as an electronics engineer, being able to look at a PCB and appreciate the ingenuity of the designer that brought it into existence, from initial ideas to implementation, from its baseline specifications to its intended functions, and from the choice of components to its final layout to achieve the best possible use of limited board space, it's more than just engineering and planning. There is an artistic beauty that is visible only to the initiated, and a hidden gem that is revealed to the keen-eyed. In every PCB there is a treasure to be discovered, some coveted design knowledge to be gained; and that is a strong enough reason and motivation for the hard work ahead.

Here are the key areas you need to pay attention to and gather as much information as you can before launching into the deep:

1.   Accessibility (probe points)

2.   Bill of materials

3.   Conformal coating

4.   Datasheets

I call these the ABCD's of preparation work. By working through these key areas, you'll gain a better overall picture of a PCB, which may help you decide if it's feasible to attempt, if you have the time and ability to do it, and whether it's worth the effort or not.

The Three D's of RE

PCB reverse engineering is by no means an easy task. Very often, it is laborious because of the repetitive nature in finding and ascertaining the electrical connections between components. Also, being able to constantly visualize the schematic diagram that is slowly taking shape and having to realign the various portions of a circuitry to ensure readability requires certain artistic affinity—a skill that can usually be picked up and refined only with practice.

Ultimately, it comes down to three essential traits that a person who wants to engage in such a work must possess in order to be able to successfully complete the task:

Determination

A 'never say die' attitude is important especially when faced with the constant frustration of not being able to locate the electrical connections to make sense out of the partial schematic diagram. This is not to say that one must be insistent on finding the 'missing link' and gets stuck on one particular part of the PCB, and not able to make further progress. Working smart is just as important as working hard!

Discipline

Being focused, systematic and maintaining a careful work practice are necessary to avoid unwanted mistakes that can prove to be both time–wasting and confusing, perhaps even to the point it demoralizes you. Many engineers have the habit of diving straight into a project or task without giving thought to at least some planning or preparation work. This is a BIG mistake that will pay grave dividends—believe me—I made them myself and thankfully survived to regret (and learn from) it!

Dedication

Nothing can replace the satisfaction of seeing a task complete if a person does not take ownership of the work and prides himself or herself in the thing he or she is doing. After all the end product bears the signature of the craftsman!

My Stand on Copyright

Whilst copyright laws exist to discourage or keep at bay would-be competitors (or even pirates) from stealing the designs and ideas for their own commercial gains, PCB reverse engineering services are still very much sought after, more as a desperate attempt to resolve the genuine problems of obsolescence or lack of support, and in such cases the PCBs reproduced are usually intended for internal consumption and not external circulation. Confidentiality and non-disclosure agreement (NDA) will also ensure that only the customer and the service provider are the only parties in the know.

It's a fine line we're treading when we do reverse-engineering of any sort. We need to ask ourselves why we're doing what we're doing, and whether we're doing it out of necessity on a personal capacity to get our job done, or out of curiosity when a certain PCB design so intrigued and interests our engineering senses that we couldn't pass it by without knowing what makes it tick. Frankly, troubleshooting and diagnosing PCBs without documentation invariably involves some degree of reverse-engineering, albeit in a less systematic and perhaps haphazard way. Prior to taking up reverse-engineering using Visio, I did what many repair technicians or engineers would do when stumped with a PCB without schematics—create partial sketches of the circuits I was analyzing, hand-drawn or with the help of primitive graphics editor.

Having said that, I personally do not endorse PCB reverse engineering to be used as a tool for anti-competition or theft of design, in which the end result is the financial lost of the rightful designer or company concerned. I believe that as an engineer, there is a code of honor to live by and uphold, by which personal enrichment and knowledge can be gained and shared, but not at the expense of others.

Legal and Copyright Issues

Probably one question you have in mind when approaching the subject of PCB reverse engineering is copyright issues.

So to what extent is PCB reverse engineering legal, and under what circumstances is it a violation of the copyright law? Given the complexities of legal terms involved, there are simply no straight answers. Still, the fact is there are companies out there openly advertising and providing PCB reverse engineering services, as well as selling software tools that perform such tasks. To my personal understanding, such services exist for some of the following reasons:

1. The PCB is obsolete and no longer supported by the original equipment manufacturer (OEM) or in some cases, the OEM is out of business and supply of the PCB is unavailable in the market. In such instances, the only recourse then is to engage these companies to reverse engineer and reproduce the PCB in sufficient quantity to extend the useful life of the system.

2. The company or OEM that designed and produced the PCB lost their design files (whether by accident or through catastrophic causes) and are still under contractual obligation to support their product before its end-of-life (EOL) period.

3. Modification to the original PCB design is required for extended capabilities but due to nature of confidentiality, the OEM cannot be involved or have foreknowledge of such changes, in which case obtaining the OEM's design files will be out of the question.

For those interested to know more about copyright issues pertaining to this subject, a good article can be found in the paper written by David C. Musker in which he presented at "Protecting & Exploiting Intellectual Property in Electronics", IBC Conferences, on June 10, 1998.

My Personal Story (Part 3)

You can see from the photo that the infrared matrix sub-assembly is quite a big board with a rectangular cutout in the middle for an array of horizontal (40) and vertical (30) pairs of infrared emitter and sensor diodes. These fit nicely around the tinted bezel display frame in which the brightly orange-lit plasma display of the display driver sub-assembly shows through.

The infrared matrix sub-assembly (top view)                                              Layout drawing

If you work often on surface-mounted or mixed PCBs, you'll notice that apart from the ICs and bigger component parts, the miniature SMT resistors, capacitors, and even semi-conductors such as the SOT package3 diodes and transistors may not have reference designators assigned to them on the silkscreen layer, and this is expected with densely populated SMT boards due to the difficulty and impracticality of doing so. The book explores how to give these nameless discrete devices their reference designators to facilitate the drawing of the schematic diagrams.

To cut the story short, in total I spent about a month drafting the parts list, gathering the datasheets, creating my first collection of Visio symbols for both the layout and schematic entities, drawing the PCB layout, and finally tracing out the schematic diagram.

My Personal Story (Part 2)

The next consideration was what CAD software to use for this endeavor. It so happened that there's an old copy of Visio Technical 4.5 lying around, so I installed and fired it up to do some fiddling around. It made an instant connection that persuaded me this was the best tool for the job! The first thing I did was produce a mechanical drawing of the front panel, as shown below, which took me just slightly over half an hour. Not bad for a start, eh?

The rear view of the unit was more complicated with the CPU board and the display driver sub-assembly visibly in view, but I managed to draw that too though at a much later date when I had the time to do so. However, I will not be showing it here since that is not the main focus of the story. Still, I'm sure you'll agree that Visio fared pretty well for illustration purposes (and we're just warming up!).

After disassembling the unit, I proceeded to analyze the infrared matrix sub-assembly and gathered whatever information I could find on its components. What intrigued me was the primitive yet beautiful design of this multi-layered PCB—the making use of narrow-angled beam infrared emitter and sensor diode pairs—to achieve the X and Y coordinates mapping for the touchscreen effect that was the usual practice back in the mid-1990 era. It had many of the elements that made reverse engineering particularly interesting and challenging, such as the peculiar shape and size of the PCB, the presence of through-hole and surface-mount components that are mounted on both sides, and the thick conformal coating. That's quite a handful for my virgin attempt but I went ahead anyway.

My Personal Story (Part 1)

As a principal engineer working in a defense industry company supporting the military, notably the air force and navy, in the area of local depot-level repair involving weapon systems that are, well, rather dated, it is inevitable that many defective PCBs that are sent to my workshop lack the necessary schematic diagrams to carry out troubleshooting analysis and repair work. Sounds familiar to some, if not many of you who are repair technicians and engineers by profession, isn't it?

My first serious attempt at PCB reverse engineering happened in the spring of 2001, about six months before the fateful 9-11 event. It was a Monday morning when I came in for work and as usual a trip to the pantry to get a cup of hot water. As I passed by the meeting room, I noticed a 16 by 12 square inches by 3-inch high item lying face down at one corner of the conference table. In the course of the day, some of us went in and out of the meeting room, taking curious peeks at the item but no one could figure out what it was doing in our work centre. It was only near lunch time when my manager came back from a meeting that he beckoned me to the room and said, "What do you think—can we repair this unit?" Suddenly it dawned on me that I was tasked to take up the challenge, being one of the senior and more experienced engineers at that time.

After examining more thoroughly I remarked, "It seems to be a high voltage display unit of some sort. We've done PCB repairs all along but this is the first time we're looking at a whole unit." Well, my hunch was right. It's a plasma touchscreen display unit used on-board naval ships. My manager related that the navy had approached him for a solution to their repair predicament—they had been sending these defective units overseas to be repaired by the OEM, and being end-of-life (EOL) items, there's no more contractual support so the cost of repairing each unit was ridiculously high. Lately the frequency of breakdowns had increased due to aging, and the navy desperately needed a solution to cut their overseas repair cost, and fast.

"Let me take this baby apart to study it. I'll get back to you in three days." And so it was that on the third day I reported my findings to my manager.

As shown in the partial cross-section, the touchscreen display unit comprises five sub-parts:

1. CPU control board

2. Display driver high-voltage sub-assembly

3. Infrared matrix sub-assembly

4. Touchscreen display frame

5. Front panel mounting

Defect symptom for this unit was no display so I worked on the display driver sub-assembly and found some faulty power MOSFETs. The parts were ordered and replaced but no testing could be carried out since there's no electrical drawing to show connector pinouts and what power to apply. The item was sent back to navy for site test and surprisingly it passed!

I was told that more such units would be coming in from the navy's back logs with quite a number of them having touchscreen with no response failures—an indication that the problem might have something to do with the infrared matrix sub-assembly. It therefore prompted me to consider doing reverse engineering for this particular sub-assembly.

Types of PCB

Printed circuit board (PCB) technology has seen a tremendous jump since its humble beginnings in the early 1900s. From simple discrete, single-sided through-hole to the complex fine-pitch, multi-layered surface-mounted board, the amount and density of components for a given PCB area have increased manifold while the overall size of PCBs have reduced substantially.

Such rapid advancements in PCB design not only present problems and difficulties to the test engineer who is responsible for writing test programs for the board, they also pose seemingly insurmountable challenges to those daring enough to re-create the schematic drawings. PCB reverse-engineering is indeed not for the uninitiated nor the faint-hearted. But for those who are willing to devote their time and energy to learn this art, the end results can be rewarding to say the least; it may even put you a cut above your fellow engineers because in the process of doing it, you not only unravel the beauty of the PCB itself, you actually gain engineering insights and ideas from the original designer's expertise and ingenuity on how a particular circuit is designed, how certain difficulties are overcome, as well as the sound practices and design techniques that are applied in the real world.

Why Bother?

That's a reasonable question. After all, there are machines out there in the market that can do the work more quickly, accurately, and reliably in a week or less, such as those shown below:

So why even bother to learn how to do PCB reverse engineering by hand? Firstly, flying probe test systems are expensive test equipment. A basic system easily costs over $100k and that's not including the software license for the reverse engineering option. Even if your company could afford it, nobody would stick out his neck to buy one unless there is strong business justification for the purchase. And we have not yet consider the training and learning curve to familiarize its process and utilization, the yearly calibration and maintenance of the machine, and the cost of ownership just continues to add up.

What about benchtop versions with semi-automated learning of circuit traces? I can think of a number of vendors that supply such a product, namely Abi Electronics, Diagnosys, and Qmax. These products may be cheaper than a flying probe test system, but not necessary affordable, easier to use, or better in delivering quality results.

As for the simpler and lower cost pizza-box system, a basic configuration with 128 channels will set you back by about $5-7k at the time of my enquiry. Abi Electronics also sells their more powerful cabinet systems that support from 1024 to 2048 channels to reduce the amount of test clipping on the PCB, but again the cost will invariably go up too. In terms of usage, after defining the components and placement the RE software will guide the operator to clip or probe in clusters, depending on the available channels, and then learns the connectivity of the PCB. The netlist generated is then exported to another EDA tool called EdWin from Visionics, a much more user-friendly and feature-rich schematic editor.

While it sounds simple enough to clip and probe circuit clusters, my experience with Abi Electronics equipment taught me the challenge is in ensuring good electrical contact between the test clips and the component pins. This means that the PCB must be stripped clean of any conformal coating, and the test clips must also be free of oxidation and the grip must be good and not weaken as a result of mechanical fatigue from frequent use. If the PCB is surface-mounted or mixed type, you'll need an assortment of SMT test clips to do the job as well, and these QFP and PLCC test clips are by no means cheap!

So the real question is, are you prepared to fork out the money up front for a one-time or ad hoc PCB repair job that requires you to do a bit of reverse engineering? I think the answer is pretty obvious.

What You Need to Know

While this book is intended for beginners interested to learn PCB reverse engineering, some background in electronics is preferred:

1. You should have a working knowledge, or at least be able to read schematic diagrams (that's the reason for buying this book in the first place—to re-create schematic drawings from a PCB!). It will be advantageous if you're already acquainted with the basic rules and concepts of what constitute a good schematic diagram, or better yet, if you have experience with some kind of EDA tools or software. You'll be able to skim through or skip over some of the basic information presented in later chapters.

2. You should be able to identify simple discrete devices (resistors, capacitors, diodes, transistors, MOSFETs, etc.), integrated circuit packages (DIP, SIP, PLCC, QFP, PGA, BGA, etc.) and modular components (DC/DC converter, etc.). But not to worry, I will provide useful pointers and tips along the way, when necessary.

3. You should have in your possession a good digital multimeter with the diode measurement function on top of the standard functions and know how to use it. I will also introduce other additional tools that will greatly aid you in your reverse engineering effort when we come to the appropriate chapter and topic.

4. You should be familiar with the color codes for certain discrete devices (resistors, capacitors, etc.) so you can read their values without having to constantly refer to the reference charts (I've provided quite a collection in the appendices). It's not the end of the road, however, if you're not able to remember what the color codes are; just that it will probably slow you down if there are plenty of such components on the PCB you're working on.

5. You should be acquainted with datasheets. Not that you're required to know all the component-related specifications, or understand every aspect of the device's performance. Thankfully no. But you do need to be able to find information like pin number, orientation, signal names, etc. and typical application examples provided by the manufacturer on how the device is used in real-life designs.

At first glance it may sound like quite a handful above, but trust me, it couldn't get any easier than what I have laid out as the basic skills required to get started. Before you even realize it, these would have become second nature and you'll be focusing on the real work!

Book Layout at a Glance

 

 

 

 

 

 

Rewards for Review!

Since publishing my book in 2015, I have received a number of good reviews from international readers on Amazon in the US (.com), UK (.co.uk) and Europe (.de). To encourage more readers to give their reviews, I am offering the following bonuses as rewards:

These through-hole Visio layout symbols include DIP-300, DIP-400, DIP-600, PGAs and ZIPs with their corresponding sockets, making up more than 200 in total.

These PLCC Visio layout symbols include most of the common through-hole and SMD configuration available.

These SMD discrete Visio layout symbols include resistors, capacitors, inductors, and common diodes and transistor packages.

This Visio Power Supply layout diagram is featured on page 116 of Chapter 3 and is a very useful example for learning how to render mechanical illustration of modules.

So if you have already bought the book but have yet to write a review on Amazon, kindly do so and email me to have these bonuses delivered to you!

Freebies for My Book!

As mentioned in my book, readers who support my work through purchases are eligible to receive free resources. These include:

1. Sample Visio drawings found in the book:

    a. A3 and A4 templates (portrait and landscape)

    b. Anonymous TTF (monospace font with a slashed zero)

    c. Layout and schematic diagrams of the simple NCR SCSI adapter card (see above)

    d. Miscellaneous Visio objects

2. SMD Code Reference Book

This pdf ebook contains over 500 pages of nearly 24,000 SMT code references to help in identifying small SMD devices with markings.Useful and practical when reverse engineering SMT type PCBs, and since it is in electronic form it facilitates ease of searching without having to leaf through a thick printed hardcopy.

3. IC Master References

Most ICs contain prefixes and suffixes that are confusing and hard to decipher. I have collated a total of 152 pages of IC component prefixes and suffixes from 90 manufacturers, a ready reference on hand to refer to and know straight away what the IC component specifications are when gathering information on a PCB.

4. IC Packages and Dimensions

This ebook contains many integrated circuit packages and their dimensions which you can reference to create your own Visio layout drawings. There are a total of 109 different drawings, ranging from the standard DIP, SOJ, SOP, SSOP, TSOP to the BGA, uBGA, QFP, LQFP and PLCC, etc.

5. Visio Layering Example PCB

This PCB is featured in Chapter 5 Advanced Topics where you'll learn one of the powerful techniques to organize and display a PCB layout (applicable to schematic diagram as well, once you understand the concept).

To obtain the above freebies, email me at: ngkt@engineers.com with proof of purchase.

Content Summary of the Book

Chapter 1

I know you're eager to get started right away, but it's good to know a little of what you're getting into before you plunge in completely. You'll need to have certain background in electronics. I'll mention some available alternatives to doing reverse engineering completely by hand, though they're not necessarily affordable unless you have deep pockets and are willing to part with your hard-earned cash. I'll also share my personal story on what started me on this journey (hopefully a good and inspiring read to you). Then there's the copyright issue which I'll give my personal take on it, before rounding up the chapter with a little work philosophy.

Chapter 2

This chapter may be thought of as a practical introduction or revision to electronics in terms of the various building blocks of a PCB—resistors, capacitors, inductors, fuses, relays, diodes, zeners, transistors, MOSFETs, and ICs, etc. You may think it's boring or too elementary but I've put in quite a substantial amount of information here, so you should be able to find some rare gems among the junks (to borrow a phrase from the PCB recycle industry). I'll deal with components without markings and reference designators, touch on a bit about conformal coatings, as well as how component datasheets will be a great help later on. These elements formed what I call the ABCD's of preparation work—an essential step that will save you a lot of time and trouble when you start to do the real work.

Chapter 3

We'll get down to serious business and start doing some interesting PCB layouts and components beginning with this chapter. I will provide a brief introduction to Microsoft Visio, the diagramming software we'll be using throughout the book. You will learn how to setup and navigate the Visio workspace, familiarize yourself with its various tools and functions, decide on which template to use or begin from scratch, create your own component layouts in relation to their datasheets, and more. I have included some of my very own PCB artworks to motivate you and show you what you can possibly do with Visio.

Chapter 4

Things will get more exciting as we begin to draw the schematics of a PCB. Besides showing you how to create the various component symbols and elements of a schematic, I will also teach you the strategic approaches to reverse engineering different types of PCBs (digital, analog, power, etc.). At the same time, you will also learn why it is advantageous to have a PCB layout and BOM in the first place. Having a good sense of proportion and direction is important, especially if your schematic diagram is going to span multiple pages; I will lay down specific guidelines so you know how to plan your schematics for better readability and consistency.

Chapter 5

In this chapter, I will show you some advanced techniques you can apply to achieve a more professional level in creating both the PCB layout and schematic diagram. One word of caution: attaining mastery of anything does come with a price tag (Einstein would agree with that, being one of the greatest minds in the twentieth century). If you're willing to put in the extra efforts, I guarantee that you'll not only excel in the art of PCB reverse engineering, you'll pick up a life skill—an attitude—that will enable you to go farther, and a new found confidence to face challenges in your engineering career.

Chapter 6

There's no limit to what you can learn or do, unless you choose to stop learning or doing. I'm no motivational speaker, though I've conducted various training courses related to my work, and some outside of my work (such as MATLAB® at a friend's training company). As such, I know the importance of life-long learning and decided to devote this final chapter to discussing some possible areas of expanding your engineering knowledge and skills.

What This Book Is About

This book will not teach you to become proficient in using electronic design automation (EDA) tools or software to produce or re-produce PCBs from schematic entry to gerber design files. It is not even intended to give you a formal study on PCB structural design and fabrication. There are many books out there that already addressed these topics and by authors who are certainly more knowledgeable and the authority in these fields.

That said, this book does impart knowledge on PCBs that relate to the subject of reverse engineering, as a basic understanding of any PCB you intend to reverse engineer is essential to your success. Also, I will be using Microsoft® Visio albeit in a generic manner to demonstrate the steps involved. You will learn to systematically assess the PCB candidates, gather the necessary information relating to its components, create the layout diagram and parts list for reference, and use relevant strategies to find interconnections to re-create the schematic diagram, as well as other essential and useful stuff.

Free resources are made available to buyers of my book. You can email me at: ngkt@engineer.com with proof of purchase to receive them. Buyers who leave reviews on Amazon will receive additional bonuses too!

Some Personal Background

I was introduced to Electronics at the age of 15 in my higher secondary school days. I was one of those fortunate batches of students—in fact, the last in-take to study basic electricity and electronics in the school's curriculum in 1978.

Electronics was totally new to me, and I had problem understanding some of the basic concepts back then. It might surprise you that I had trouble figuring out the milli-, micro-, nano-, Kilo- and Mega- prefixes in Ohm's Law, struggling with corrections and re-corrections in my class assignments I almost gave up the subject for fear and frustration. Thankfully the light bulb turned on in me after a harrowing first semester, and from then on there was no looking back as I went on to do well for my final exams and did my major in Electronics and Communication for my tertiary education.

Due to family financial difficulties, I signed up with the Republic of Singapore Air Force (RSAF) after my graduation as an aircraft radar and communications (RC) technician. I did well in the Air Engineering Training Institute (AETI) and was selected for the E-2C Hawkeye program. In May of 1986, I attended a six-month training at the Grumman Aerospace Corporation's premise in Long Island, New York. There for the first time, I was introduced to the concept of automated test systems (ATS) as I learned how to operate and maintain the CAT-IIID and RADCOM test stations, and used these awesome equipment to perform test diagnostics on 75% of the E-2C's sophisticated avionics (radar, communications, navigation, displays, power supplies, etc.)

My invaluable experience as one of the pioneers in setting up the E-2C squadron's third-line repair bay and running the daily maintenance operation, as well as training three batches of local technicians, laid a solid foundation for my engineering career in electronics, so much so that I was head-hunted and invited to join Singapore Technologies (ST) Electronics Limited, a subsidiary of Singapore's home-grown defense industry, ST Engineering Limited, right after my first contract with the RSAF expired. I've been with the company since for over 23 years and now a Principal Engineer by title.

Learning is a life-long process. The same is true in electronics and in the field of test engineering, which is still my primary job scope and interest. I've worked on a variety of printed circuit boards (PCBs) from through-holes using the humble TTL logic circuits, to the high-density surface-mount type multi-layered boards containing complex VLSI, FPGA and ASIC BGA chips. The rate at which integrated circuits grow in complexity and density is staggering, especially in the last decade or so.

In this book, I will share what I've learned in my years of working on PCBs with no schematic diagrams, my approach of assessing a PCB, analyzing and reconstructing its electrical connectivity, the tools and methods I employed, useful tips to take note, as well as pitfalls to avoid. Sprinkled in the footnotes you will find some interesting anecdotes and personal takes to keep the subject of this book light-hearted and (hopefully) engaging.

Dedication

This book is dedicated to all electronics enthusiasts who share the same passion and appreciation for printed circuits and possess the curiosity and tenacity of engineers to unravel the beauty of the original design.

Acknowledgement

This book would not have been possible without the understanding and support of my wife, Bernice, when I expressed to her my desire to write a book of this nature that is totally outside her knowledge domain.

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The information, examples, illustrations, documentation, and other references in this website are provided "as is", without warranty of any kind, expressed or implied, including without limitation any warranty concerning the accuracy, adequacy, or completeness of the material or the results obtained from using the material. The owner of this website shall not be held responsible for any claims attributable to errors, omissions, or other inaccuracies in the materials presented. In no event shall the owner be liable for direct, indirect, special, incidental, or consequential damages in connection with, or arising out of, the construction, performance, or other use of the materials contained herein.