Book Review Out of the Blue...

These days it's hard to find readers who appreciate my books enough to leave a nice review on Amazon. So I was presently delighted that someone left a glowing review for PCB Diagnostics which I've written about three years ago:

Excellent overview, really the only book of its kind. Getting back into advanced PCB diagnostics/repair having not worked in the industry for over 20 years, this book was a phenomenal refresher, so much so, I have several more of Mr. Ng's books awaiting to be read. 

I see another review complaining the book is full of expensive equipment, it does cover various things like A.T.E. and such systems, but also teaches the basics of diagnostics. I would say anyone coming to this book without sound electronics knowledge in the engineering realm will find themselves out of place with the material, but more so out of place if trying to do any such work. This book isn't for the part and board swappers looking for easy tricks that will fix PCBs, that is for youtube. If you really want to get into the field you need to hit the books and bench, use this as a guide for futher education.

If you, my reader and follower of this blog, have received the benefits of my hard-earned engineering insights and experience, would be kind to leave a good review on Amazon, it would definitely help in the ratings and sales to enable and motivate me to write more in the future. 

My wife, who supported me all these years in this gruelling work, always look forward to reading them, and find consolation that our efforts do make a difference and impact in other people's lives.

So have a heart and do your part. Hear from you soon! 

Repair, New, or Refurbished?

Question: 

Your plant has a 15-year-old conveyor motor that fails every 4 months. Each repair costs $300. A new motor costs $2,500. A refurbished motor (from a specialist) costs $1,200 with a 1-year warranty. Which path do you choose? What data would change your answer? 

Answer: 

Given: 15 years old, fails every 4 months → 3 failures/year × $300 = 900/year. New = $2,500; Refurbished = $1,200 with 1-year warranty. 

Simple payback (repair vs. refurbished): 

Current annual repair cost = $900.  
Refurbished cost $1,200.  
Payback = 1.33 years.  

After 1 year, warranty covers failures. From year 2 onward, assume refurbished failure rate is similar to current (3 failures/year) → another $900/year. Still cheaper than $2,500 for new. 

Decision: Choose refurbished motor based on current data. 

What data would change answer? 

▪ If the conveyor is a production bottleneck where downtime cost is >$500/hour → new motor (higher reliability) may be justified. 

▪ If the refurbisher's warranty excludes labor, adding $150/failure for installation → refurbished TCO rises. 

▪ If the motor is obsolete and refurbisher uses scavenged parts with unknown remaining life → avoid. 

▪ If new motor efficiency is 10% better, then electricity savings alone could favor new motor over 5+ years.