To My Readers



If this is the first time you're visiting my blog, thank you. Whether you're interested or just curious to find out about PCB reverse engineering (PCB-RE), I hope you'll find something useful here.

This blog contains many snippets of the content in my books to provide a more detailed overall sampling for my would-be readers to be better informed before making the purchase. Of course, the book contains more photos and nice illustrations, as evidence from its cover page. Hopefully, this online trailer version will whet your appetite enough to want to get a copy for yourself.

Top Review

I started doing component level repair of electronics with (and without) schematics more than 40 years ago, which activity often involves reverse-engineering of printed circuit boards. Although over the years my technical interests have shifted into particle beam instrumentation, electron microscopy, and focused ion beam technology fields, till this day——and more often than not——PCB repairs have returned multiple multi-million-dollar accelerators, FIB, and SEM instruments back to operation, delivering great satisfaction and some profit.

Many of the methods described by Keng Tiong in great details are similar to the approaches I've developed, but some of the techniques are different, and as effective and useful as efficient and practical. Systematic approach and collection of useful information presented in his books are not only invaluable for a novice approaching PCB-level reverse engineering, but also very interesting reading and hands-on reference for professionals.

Focus on reverse engineering instead of original design provides unique perspective into workings of electronics, and in my opinion books by Keng Tiong (I've got all three of them) are must-read for anybody trying to develop good understanding of electronics——together with writings by Paul Horowitz and Winfield Hill, Phil Hobbs, Jim Williams, Bob Pease, Howard Johnson and Martin Graham, Sam Goldwasser, and other world's top electronics experts.

Valery Ray
Particle Beam Systems Technologist

Saturday, March 4, 2017

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.


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