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

Tuesday, June 2, 2026

The Refurbishing Workflow


If you're doing a one-off refurbishing job in your daily repair work, then a workflow may not really matter much. But if you're thinking of making refurbishing a sustaining business model then it is imperative to adopt a proper process to ensure success.

Refurbishing follows a repeatable workflow, though the depth of each step varies by product type. Of interest is the first step: Intake/Triage. What exactly is triage, you might ask. In refurbishment, it refers to the initial, rapid assessment and sorting of returned, damaged, or aging items to determine the most cost-effective action: repair, refurbish, resell, or dispose. This process prevents wasting resources on irreparably damaged items and prioritizes those that can be quickly returned to the market. 

You might not realize it but intake triage is the most economically critical stage. A misclassified unit will lose money at every subsequent step. Here's an economic triage rule you would do well to adhere to: 

A product is economically viable for refurbishing if (Resale value of refurbished unit) – (Cost of parts + labor + overhead) ≥ 30% of resale value. That's the minimum margin threshold and it varies by business model. If the margin falls below this threshold, the product is better used as a donor unit or sent to recycling.

A "donor" unit in refurbishing refers to a used, broken, or identical device (often a hard drive, appliance, or electronic component) that is utilized to supply parts for the repair of a "patient" device. This process allows technicians to restore non-functional equipment to working condition by replacing damaged, rare, or obsolete parts that are no longer produced. It's also referred to as "parts harvesting".

It is also important that each unit received during the intake has a unique tracking identifier (serial number, barcode, or RFID). This ID follows the product through all six stages, creating an audit trail. It ensures traceability, compliance, and quality control, providing visibility into the "who, what, and when" of the refurbishing process. 

Bet not many know of such details involved in starting a refurbishing business. There's more but I'll stop here for now. Once I sort out the workflow process in my upcoming book, you'll have the needed information all in one place.

 

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