Troubleshooting SMPS

Troubleshooting & Repairing Switch Mode Power Supplies

by Jestine Yong

Wow! I’ve read and reviewed a couple of Jestine’s earlier books and they have all been extremely informative.  This book is no exception!  It is jam packed with tons of useful information.  It would be a bargain at $100 or even $150.  I can remember in college (over 30 years ago) paying over $100 for a textbook that didn’t have half as much useful information.  If you have zero experience in electronic troubleshooting, get this book after you have his earlier book, Testing Electronic Components.  The reason is that troubleshooting a SMPS is not for raw beginners, you need to understand the basics first. You know, crawl before you walk…

This book is divided into five major sections:powersupplysmall

  1. Introduction to the SMPS
  2. Secrets of SMPS troubleshooting techniques
  3. Case histories
  4. Troubleshooting and repairing ATX (computer) supply
  5. Miscellaneous

Briefly each section covers:


The introduction offers you an overview of how an SMPS works and the major circuit sections your are likely to find.  He also discusses, briefly, the components, their likely mode of failure and how to identify and locate the correct replacement part.

Secrets of SMPS troubleshooting techniques

He discusses the required and nice to have test equipment and the safety requirements.  In this section he assumes that you already have the basic tools like a soldering iron and vacuum.  If you’re brand new to electronic troubleshooting, please get his earlier book first as it covers the basics.  He then discusses the 6 most common SMPS failure modes.  Remember, not all problems are the power is off.  One of the secrets he talks about is a technique I learned over 25 years ago when I was experimenting with Tesla coils.  It involves using a common household light bulb and will save you literally hundreds of dollars in additional repair parts, but more importantly it will save you hours and hours of troubleshooting time and frustration.

Case Histories

powersupplysmallThis is my favorite section.  Why? Because you get to go inside his head and understand how he thinks.  For every power supply failure mode, there is a nearly infinite number of ways that it could happen.  No book, can tell you if this is the symptom, replace this component.  They can only tell you if this is the symptom, here are the likely causes.  The best way to learn the craft of repairing SMPS is to do it.  By presenting you different failures and not only the how, but why he trouble shot in a certain order, you get a better understanding.  He stresses that not everyone operates in the same manner or order, but by knowing his technique you are exposed to a logical methodology.  I troubleshoot some things the same way he does and others differently, but that’s OK and he explains why.

ATX Power Supply

The fourth section is devoted to the ATX power supply.  While the title is ATX, the similarity of computer power supplies is so great that it will work for nearly all.  The ATX, being the most common, makes the most sense.  It has another case history which is awesome! Assuming you’re doing this as a business venture this section has some great advice, read it carefully.

The last, miscellaneous section covers all the odds and ends that aren’t covered elsewhere.



My complaint with the book?  It’s really quite trivial, but here we go.  There are no links in the book from the table of contents to the text or from the text to other sections of the text that are referenced.  That’s it format…  The content and order of the book is logical and highly valuable and as I said earlier would be a bargain at a much higher price.


In summary, if you would like to learn the intricacies of SMPS troubleshooting and repair, this is the book for you.  It is full of practical, real world, information that can be put to immediate use.  If you have little or no experience troubleshooting then I would recommend you buy his earlier book, testing electronic components first before this one.  There are too many fundamentals that can’t be covered in this book unless it was two or three times it’s present size.  My experience is that power supplies are about 3/4 of the problems with electronic devices.  I remember one of my college professors telling me that power supplies should be designed with plenty of “head room” ( extra capacity) as they were the source of the majority of the problems, how true.

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{ 4 comments… read them below or add one }

jose w November 3, 2011 at 21:14

this looks useful for smps trouble shooting


Dan November 18, 2011 at 10:55

it is a great book and as I said, I highly recommend it. For more generalized troubleshooting you might want to check out the “Part testing” page
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smpstroubleshooting December 18, 2011 at 02:13

Thanks a lot!
smpstroubleshooting recently posted..SMPS TroubleshootingMy Profile


Adnan December 20, 2011 at 16:20

Can you send me this book at please?I would appreciate it:)


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