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

Thursday, March 23, 2017

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.

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