Latest update: 5-2024
The tutorial has had updates as of May, 2024 (actually, it's been getting daily revisions). If you purchased it in the past, you can download the latest version, free of charge. All I need is proof of purchase (PayPal notice). It's likely still in your email inbox list (use the search function and search for my email address, If you can't find it in email, you should be able to get it from your PayPal payment history. If you can't find it, give me the email you purchased it with and I'll see if I can find it.

For those new to the repair tutorial and need to know what's included, click HERE to jump past the short version.

For those who are here to find what's involved in purchasing and downloading the tutorial, continue below.

This tutorial is for those who are serious about learning to repair car audio amplifiers of all types (class B, class AB, class D). Many of the circuits being used today have been in use for 20+ years. Some of the common class D circuits in use today (and covered in the tutorial) date back to about 2003. The material covers overall design and the components/circuits commonly used in many of those amplifiers.

While this is centered on car audio amplifiers, much of the information applies to electronics in general. If you're interested in getting into the hobby of electronics, this will help ease the learning curve.

On the DIYAudio forum, I have more than 50k posts helping others try to repair amps. Feel free to read the various repair threads. My user name is Perry Babin.

One more quick note... If you're going into a field that involves electronic design, especially if audio is of interest to you, this tutorial is an excellent way to connect the dots between the theory taught in schools and the real world. I thought that after getting an education that I would be able to look into a piece of electronic equipment and immediately fully understand what I was looking at. It's not that straightforward. Sure, the knowledge gained in school taught me a lot but certainly left a lot to be learned as it related to pieces of electronic equipment.

One last thing... I'm not politically correct. I don't intend to offend anyone but I also don't try to hide my contempt for those who do shoddy work, those who refuse to do what's required to do what they claim to want to do or for those who cheat those they do work for. If you fall into any of those categories, expect to be offended.

Learn To Repair Car Audio Power Amplifiers
Let 30 years of experience help you to succeed
If you purchased the tutorial and are having trouble getting the files installed, click HERE.

  1. Introduction
  2. What this Tutorial will do for Someone New to Car Audio Amplifier Repair
  3. Samples of my Other Work
  4. Test Tone CD
  5. Updates
  6. Previous Updates
  7. Cost of the Tutorial

To be clear about the content...
This is not a video tutorial. It's a web-based file in the same format as my Basic Car Audio Electronics website that you will view with a web browser on your computer. There is no significant video content included with the tutorial. It's mainly interactive demos, text and images.

This tutorial contains interactive Flash graphics and cannot be used with a modern browser since Adobe and new browsers have seen it necessary to block Flash. There are multiple options for viewing and interacting with Flash content. Some can be found here. Basically, it's as simple as using an older browser like Safari 5.1.7 and installing the old (still working _371) Flash Player files.

Summer's coming. The hot weather will increase the number of amplifiers failing.

  • Introduction:
    The information contained in this tutorial is from 30 years of experience working on amplifiers such as those from Rockford, Sony, Autotek, Coustic, Planet Audio, Kenwood, Pioneer, JVC and just about any other brand sold in the US. This tutorial has information and tips that will help you repair hundreds of different models of amplifiers. It is also interactive (demos allow you to change the input values on various sample circuits and see how the output changes). There are no service manuals (service information provided by the manufacturer for a given model of amplifier) from any company that are even remotely interactive. Since many amplifier manufacturers offer zero tech support (not even schematic diagrams), this may be one of the few sources of information to help you repair some models. For car audio amplifiers, there is nothing else like this at any price.

    This tutorial contains a considerable amount of information specifically related to troubleshooting at the component level. It includes commonly used alternate part numbers for the most common semiconductor failures. If you want to get into the repair business, this disc will provide some very important information. If you are already in the repair business and are interested in repairing car amplifiers, this tutorial can help you get started with very little effort. If you are in the repair business, you already know that more and more equipment is disposable (not worth repairing when it breaks). Car audio amplifiers are one of the few money making types of consumer electronics to be repaired.

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  • What this Tutorial will do for Someone New to Car Audio Amplifier Repair:
    The information provided in this tutorial will help you to avoid making the most common mistakes and will greatly increase your chances of success. As you read through this page, you'll realize that the new amps are much more complex and much more difficult to repair than the old school Rockford and Orion amps that started the car audio revolution. This tutorial makes getting started much easier.

    Many people ask for personal instruction to help learn to repair amplifiers. In most all cases it's impractical and would be prohibitively expensive (considering that most experienced techs charge between $60 and $100 an hour as their base labor rate). Compare the equivalent to one hour of a tech looking over your shoulder while you're working on an amp to what you get in the tutorial. In one hour, you'd likely not even be able to finish a single repair. During that repair, the tech would be able to give you a few pointers and possibly a few specifics but unless you were taking accurate notes (which would cut into that hour), you would not remember much of what you were told. For the price of the tutorial, you get graphics, clearly written notes, a few video clips and many real world examples relating to actual repairs. This gives you the ability to go back and review the information to refresh your memory or to read something you may have missed the first time you read through the material.

    The basic repair tutorial (free online) is far more than you'd get in an hour of personal instruction and the information there is absolutely insignificant in scope compared to what's in the full tutorial.

    The tutorial begins at the most basic level. There are suggestions for the types of amps you should start with and those to avoid until you have a bit more experience... and advice for amps that you should avoid altogether. For amplifiers with common problems, you are told what to look for and how to correct the problem so that the amp is, many times, more reliable than when it rolled off of the assembly line. Of course, the information goes well beyond the basics. For those who are at a more advanced level, information and suggestions are provided for some of the largest amplifiers currently on the market. Although this project began in 2002, the information covers many of the amps from the early 80s as well as some of the newest amps on the market. The information is continually being updated to insure that the information continues to be both useful and relevant.

    I help quite a few new techs. There are some that have been struggling for more than a year (sometimes quite a bit longer). It's clear that some things are not obvious and without the knowledge of an experienced tech, the same mistakes are made time after time. From what I see (from those with and without the tutorial), the information in this tutorial can take at least a year off of the learning curve. Without the information in this tutorial many techs, even 2 years on, are making costly mistakes that they would have avoided.

    It may seem like I'm simply trying to increase sales by using using scare tactics. That's not the case. In fact, if I believe that someone isn't well suited for this type of work, I'll tell them that they should not buy it. As an example, if you 'think' you're interested in doing this type of work but couldn't be bothered to read 100% of the basic repair page online, you are not a good candidate for this type of work. If someone is genuinely interested in learning to do this type of work (either as a hobby or professionally) and they don't want to learn by trial and error (which generally means lots of expensive, frustrating errors), they can do no better than the information in this tutorial. The circuits in many of the new amplifiers are almost impossible to understand without help and there are very few options when you need amp repair information. There may be only a few people on the entire planet that are willing and capable of helping you. You can find plenty of people who are willing to provide dangerous and costly advice but it takes someone with real experience to point you in the right direction.

    After the purchase, I will gladly provide support (via email) for amplifiers with which I'm familiar. If you need help with an amplifier model that I've never had on the bench, I'll provide suggestions to help you through the troubleshooting process. I'm generally available more than 12 hours a day. I also help those who haven't purchased the tutorial. If you have a question about a repair, feel free to email me. If you haven't seen it yet, I have a basic repair information page on my car audio site. THIS is a direct link to the page. If you need help with a repair, please read that page very carefully and in its entirety. It will allow you to ask questions and present information in a way that makes helping you as efficient as possible.

    To the fathers who are interested in car audio electronics and are struggling to get their sons away from video games, this may be something that both of you can be interested in (especially if they're just getting a car).

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  • Samples of my Other Work:
    For those who found this page from a Google search, do not know me and are not familiar with my websites, you can visit them by clicking the links below. The tutorial is in the same style as the Basic Car Audio Electronics website but contains a wealth of information related to repairing car audio amplifiers that is not included on the site.

    Basic Car Audio Electronics
    Amplifier Repair Primer
    Amplifier in Protect Mode - Troubleshooting
    Shield Ground Testing for Head Units
    Basic Computer Operation Tutorial
    Basic Macro Photography Tutorial
    Air Rifle Links and Demos
    Basic Go-Kart Mechanics

    You can also find me on the DIYAudio forum if you need help with a repair.

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  • Test Tones CD:
    Only available with tutorial purchase.

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  • Updates:
    There is information on amplifiers from the 1980s up until many currently being produced. Many of those designs have been in use for years and will continue to be used in newer amps. Typically, amps are updated externally but use tried and true designs internally. It's sort of like a car engine. They don't design a brand new engine from the block up for every new year model.

    Old text:
    I will no longer list every new item in the updated version of the tutorial. Realize that most amplifiers in existence are using designs from well before the last update of this tutorial. More updates are coming but don't let the date of the last noted update make you believe that it's obsolete. The IC that's used in MANY of the largest amps on the market was released in 2006. Virtually no amps on the market use technology that hasn't been in use for at least 10 years.

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  • Previous Updates:
    The following list of updates will give you an idea of what's in the tutorial. If you have questions about specific information regarding the content of the tutorial, feel free to email me at

    December 2014 -- Updated!
    • At least 5 of the Tech Tips pages have been improved or have new content.
    • More information on class D amplifiers using the HIP4080 has been added to the Basic Class D Troubleshooting page.
    • New substitute parts have been added for some hard to find parts.
    • The general notes pages for the MTX and Kicker amps as well as the MTX 7801 and 81000 have been updated
    • On the Power Supply Troubleshooting page, information for the Pioneer PA2027A has been added. This IC has been confusing for a lot of new technicians, mainly because the internal circuitry is rarely provided in most Pioneer service manuals.

    June 2014 -- Updated!

    I don't generally list updates and there have been many between 2011 and 2014 that are not listed but I decided to list these because some were fairly significant, especially those for several types of class D amps. Most of these updates were produced between January and June of 2014.

    • If you repair the older BD type amps (BD1000A1 and similar), there have been significant updates with regards to simpler troubleshooting. The information allows you to troubleshoot with little or no risk of damaging components if you make a mistake. The troubleshooting is much more step by step than it was before.
    • For the relatively new amps like the T1500-1bd, new information and troubleshooting techniques. These allow you to test the drive circuits with virtually no chance of causing damage to the output transistors if there is some un-expected problem with the drive circuit.
    • There have been significant updates to the Basic Class D Troubleshooting page. Significantly more information has been provided for the protection circuits as well as other troubleshooting. This applies to many of the Hifonics and similar amplifiers that use the HIP4080 driver IC.
    • Many of the graphics (static and interactive) have been updated/replaced/added. Many make it easier to understand the related text.
    • Many of the various Tech Tips have been updated. Some new ones added.
    • The older Rockford amp page (old style punch 45/150, etc...) has been updated with new, cleaner graphics as well as other information.

    Like the rest of the information included in this tutorial, you won't find information like this anywhere else. Most of the information you find on various other sites (especially those with videos) is incomplete and can often lead to more damage than was present initially.

    December, 2011 -- Updated!
    • A new type of class D amp is added to generic class D section. The new page is Generic Class D - Type 7 for those who already have the tutorial. This type of class D is particularly prone to failure due to the high operating temperature of the components on the audio driver board. The page shows the parts that fail and shows the components needed to make a heat spreader to reduce the operating temperature of the two drivers that get so hot (under normal operating conditions) that they will damage the board. The materials used are quite difficult to find if you don't know exactly what to look for. It also gives an overview of the way the power supply voltage is produced for the driver board.
    • I've found that certain pages continually need to be referred to by myself and buyers. To make it easier to go to the most commonly referred to pages, I've added a quick-link directory above the rest of the directory items. These include links to all of the class D and tech tips pages in the directory as well as the audio and power supply troubleshooting pages.
    • The basic class D troubleshooting page (which covers a wide range of amplifiers) has had quite a few updates including more clarifications/specifics, additional content and new graphics.
    • The vintage Orion amp page has been updated to show one common type of damage done by new techs and how to make the repair of the damaged area reliable if you happen to see this type of damage. Additional information is provided to show how to quickly remove the blue insulator material from the backs of transistors without making common mistakes that will lead to more damage.
    • The Vintage Rockford page has also been updated to better help those who are trying to get their old school amps working again. For those who have purchased replacement driver boards for their old DSM amps and can't determine which way to install them because they look completely different, a new image shows you precisely what to look for on the two boards (old and new) to get them properly installed. For those who have amps with broken bass and treble pots and cannot find replacements, a new image has been added to show the value of the resistors and how to install those resistors in place of the broken/missing treble pot. The amp will operate perfectly fine without the bass pot but will self destruct or destroy speakers if the treble pot is missing.
    • A section has been added to show how to view waveforms using the scope in differential mode. This is very useful when you have a waveform with relatively low amplitude that's biased with significant DC. This is NOT the same as switching to AC coupling. This is on the Tech Tips 8 page. Other information has also been added to that page.
    • The Checking Semiconductors has been updated to better explain the transistor/semiconductor testing process.
    • New techniques are shown to desolder solder pads in tight locations when you want to replace an IC or other component from the top of the board. This helps prevent burning adjacent components (most often capacitors). The burning of the capacitors isn't often a problem but it looks bad and can be avoided. Many techs would say that it's best to remove the entire amp from the sink and replace the component by desoldering/soldering from the bottom of the board but that's impractical on amps that take hours to disassemble and reassemble when only a single op-amp needs to be replaced.
    • More information about a different version of the Class D - Type 2 amps. This is one of the most popular cloned circuits and is used in many thousands of amps that have been produced. This is a new board and layout and it has its own (new) list of problems. This page has had other updates also regarding the older boards. It seems that these amps have a never-ending list of problems and without knowing what they are, the amps will boomerang on you virtually every time you repair one.
    • The Terminal Blocks page has been updated to provide more information/help when dealing with melted terminal blocks. This is a very common problem and if you don't have any experience or guidance when repairing them, they can be very time consuming to repair. Replacement blocks are typically VERY difficult to get and repairing a block, even if its housing is a bit melted/distorted, is better than running wires out of the amp (in most cases).
    • The oscilloscope page has had some updates including new graphics and content. Since many people that use the basic repair page online needed this information, most of the information is available on page 73 of the site (page numbers won't show up in Chrome or Safari but will show up in Firefox and IE).
    • Other minor additions...
      • Getting contact cleaner into potentiometers that don't have any apparent openings
      • Taking voltage readings on ICs that are mounted on vertical boards and can't be probed with standard probes
      • Determining whether a board has more than 2 layers of copper and finding openings in the inner copper (in case you need to drill into the board)

    July, 2011 -- Updated!
    • Much of the new information that has been added recently is from questions that I receive via email and from the car audio forum at the site. After doing this work for as long as I have, it's easy to take for granted that those new to repair will understand certain points. For virtually any question that I've seen more than once, I've included information that clearly answers those questions.

      A few examples...

      • Drivers were mentioned and most people understood them but there were enough that remained somewhat confused so I added quite a bit of information on drivers and provided several example with photos.
      • Disassembly and cleaning of potentiometers was covered because it can be useful and isn't something that's intuitive. I thought cleaning potentiometers (without disassembly) was obvious but it appears that it wasn't so I've added a section that explains how to clean various types of potentiometers without disassembling them.
      • The removal of spring-clips was covered but I didn't cover getting the really stubborn ones off. That's now included.
      • Some terms have been better defined and a few more added at the beginning of the tutorial. Virtually all were introduced when they needed to be but it seems that it's better to introduce some of them earlier. This seems to help some of those new to repairs.
      • More information has been added for those who don't yet have a scope to help them to better understand what their meter is telling them.

      These are only a few examples of the new content. Some new graphics have been added and some images were replaced as better examples became available.

    November, 2010 -- Updated!
    • A new page has been added to help introduce head unit repair. This page includes a number of tips to help you avoid costly mistakes. Head units are very fragile compared to amplifiers and simple mistakes can cost $50 or more to resolve. It currently covers ribbon cable replacement, power amplifier IC replacement and several other common repairs.
    • A tutorial for a relatively new type of class D amp has been added. This is Class D - Type 6 for those who already have the tutorial. The page includes voltages and waveforms (like the pages for other types of class D amps).
    • Additional information has been added for amps that use multiple power supplies (both in series and in parallel configurations).

    July, 2010 -- Updated!
    • Again, there have been lots of minor updates and improvements. Additional information has been added to many of the pages. Several new pages have been added, including the new switching power supply design tutorial (which covers the actual design of a power supply suitable to power a car audio amplifier). Since so many aspects of amp repair have been covered previously, there are unlikely to be any significant additions unless a new type of amplifier is introduced. Most of the changes will be minor (but useful) updates that continue to make this tutorial as good as it can possibly be.

    December, 2009 -- Updated!
    • As usual, there have been lots of minor updates and improvements. Approximately 40 pages have been edited to make them better (including more images).
    • On the power supply troubleshooting page, more information has been added that shows multiple transformer configurations (some of which are only now being introduced in the newer amps).
    • On the Checking Semiconductors page, graphics have been added and improved to make them more clear. Additional text has also been added to make it easier to understand the process of checking transistors.
    • On the Amplifier Basics pages, there are improved graphics as well as additional information.
    • On the Basic Class D troubleshooting page, additional information has been provided covering the over-current protection circuit used in many of the class D amps.
    • An entirely new page has been added covering a type of class D amp that has not previously been covered. This is a relatively new design and not much is available elsewhere for it.
    • The items above are just a few of the improvements made in the last 6 months.

    June, 2009 -- Updated!
    • There have been many updates since September. Here are a few of the more important ones.
    • I've added a page to help troubleshooting the class D amps similar to the Massive 1500 and 3000 that are so popular. The information includes waveforms and instructions to test the circuit with and without the output transistors in the circuit. This can be very helpful if you have an amplifier that's drawing excessive current.
    • A new page has been added that shows how to make an inexpensive heater/pre-heater that can make removing SMD electrolytic capacitors much easier and reduce the chance of damaging the solder pads. This is especially helpful when working on boards with a high density of components. This page also introduces you to using solder paste.
    • More information has been added for the class D amps with the numbers machined off or encapsulated in epoxy (including information on how to safely remove the epoxy to allow replacement of the ICs under it).
    • More information has been added to show you how to repair badly damaged boards. It includes information on the best type of fillers to repair holes (when necessary).
    • A section has been added for rewinding transformers. Many times, the power transformer will short and the windings will be burned. Sometimes it's as simple as removing the old wire and re-winding it. Sometimes the core is damaged and isn't usable. I've provided sources for both the magnet wire and the cores and suggestions for the type of core material you'll need to select.
    • More information on protection circuit troubleshooting has been added. This seems to be one of the most difficult types of problems for new techs.
    • Many times, an amp will have water damage that will cause damage that's nearly impossible to see. To make it worse, the manufacturer of the amps that most commonly have this problem will provide absolutely no tech support. A section has been added to tell you what to look for. The signs of damage are very difficult to see until you know precisely what to look for.
    • Many amps have terminal blocks that can't be readily soldered. I found a solution and show how to make the blocks solderable. This is becoming a bigger problem as these types of terminal blocks age and the solder connections begin to fail.
    • More than 800 files have been updated since September. Many of the graphics files were replaced with better ones or cleaned up. Virtually all of the text based pages in the repair section have had some information added or have had sections re-written to make them better.

    September, 2008 -- Updated!
    • I've added more parts suppliers and additional resources to find parts. This helps save time when looking for replacement parts.
    • I've added to the list of Tech Tips including a section on rewinding failed power transformers. It includes sources for the wire and cores. If you have to rewind or replace a transformer in an amplifier this will make the task much easier.
    • I've expanded the page dedicated to terminal blocks. Most people don't think about the terminal blocks when repairing an amplifier. Many times, the blocks are damaged so badly that they're not usable. Most are not available from the manufacturer. If you repair an amp with damaged terminal blocks (something that's not always obvious) and you don't have the knowledge to repair the blocks, you've wasted your time repairing the electronic faults in the amplifier. Of course, I've added new amps with the screw sizes. Some of the other improvements are better graphics and more detailed information about obtaining replacement screws.
    • I've expanded the section that shows you how to produce reliable repairs on badly damaged circuit boards. If you work on old school amplifiers, this information can help you make repairs that will be very reliable.
    • To make troubleshooting easier, more information showing the voltages on the pins of various ICs have been added. This allows you to confirm that the voltages in the amps are as they should be. This is something that will continually expanded in the future.
    • Even more information has been added for class D amplifiers. As always, I try to keep the information as up to date as possible. This information pertains to many of the amplifiers that use the audio driver boards with the defaced driver ICs.
    • Since March, more than 100 pages have been updated in some way. More than 300 graphics files have been added, replaced or improved in some way.

    March, 2008 -- Updated!
    • Lately, I've been working to make the tutorial more user friendly. Many of the most recent updates involve linking relevant pages to the text. I've also been trying to clarify information to better suit those new to repair work. I use questions from buyers (and others who I help with amp repairs) to make the information easier to understand.
    • I've added markers to pages that show you the information you should print and keep handy while working on the first few amps. These 'cheat sheets' will help you troubleshoot the most common faults.
    • Of course, I've added new information. New applets, as well as lots of new graphics showing examples of various problems and solutions. Approximately 400 graphics files have been added or modified/improved since the last update. In some cases, I've replaced older, smaller graphics with new or resized graphics. Some of the original graphics were designed when 800x600 was a commonly used screen resolution. The new, larger graphics allow you to see much more detail at higher screen resolutions.
    • A new page has been added to help you clean really noisy potentiometers. Many of the potentiometers are very difficult to obtain as replacement parts. This will help you salvage some of the potentiometers that are not readily available. This goes well beyond spraying contact cleaner into the pot and turning it. It also explains how things other than a dirty resistive track can cause problems.
    • I've added more information on class D amps. Some of this information covers a relatively common problem with one type of class D driver board. This is a problem that took quite a bit of time to find initially but has saved many hours of wasted time for other amps with similar problems.

    September, 2007 -- Updated!
    • For many of the amplifiers being produced in China and Korea, the manufacturers will not provide schematics (they probably don't want you to know that they can't/don't design their own amplifiers). Fortunately, MANY of the manufacturers use precisely the same circuits. If you've ever been to the ampguts site, you've no doubt seen how many of the amplifiers use precisely the same board (this is particularly true for class D amplifiers). I've collected several schematics that cover most of the Chinese/Korean amps and I group them together so you can see which schematic to use for a given type of circuit. The schematics won't always match 100% but in most cases, they make it MUCH easier to troubleshoot the circuit.

    July, 2007 -- Updated!
    • I've significantly expanded the information provided for one of the two most commonly used class D amplifier circuits (multiple manufacturers use the same PWM drive and output circuits - Kicker, Orion, JBL, Memphis...). The information includes waveforms from virtually every point in the PWM generation/output circuits.
    • For those with minimal skills when working with metal, I've included an entirely new section. It shows tools (and the use thereof) that are required when there are issues with the heatsink or when you need to produce new clamps (for missing or melted clamps). This doesn't happen often but it's good to know. This is a companion to the MEHSA replacement tutorial I added last month.

    June, 2007 -- Updated!
    • I've added a page detailing the replacement of the MEHSA insulators if you'd like to do away with them. The section includes relatively detailed instructions on making the replacement clamps. I tell you how to accurately measure the distance between centers for the mounting screws (holes have to be drilled in the clamps). I suggest some free cad software to help you in the process. I even show you the finished clamp on an 800a2. This also comes in handy for amplifiers where someone has broken off a screw in the sink. In this example, they had tried to remove it which made it too much of a mess to try to repair. A new, heavy duty clamp (made to apply sufficient pressure to the transistors adjacent to the missing screw) got the amp back into service reliably.
    • I've added at least one example of an amplifier that had a badly damaged board. The repair on it left it stronger than it ever was and there was little evidence that it was so badly damaged. This was one of the times when it was important to have some mechanical aptitude to get the job done.

    April, 2007 -- Updated!
    • I've added a significant amount of new information about special/unusual resistors and capacitors. This includes information on how to read their values and what the markings mean.
    • I've added a page that offers several solutions for customers who repeatedly burn the RCA shield on their head units. Open shields on the signal source can cause some amplifiers to fail. This will save you some headaches with certain types of problem customers.

    March, 2007 -- Updated!
    • I've added a new page giving suggestions on making ultra reliable wiring harnesses for the workbench. It's vitally important to be able to trust your test equipment. This includes the bench wiring. Some of it takes a beating. The tips I provide will insure that you don't have to continually repair the cables you use repeatedly all day long.
    • The 'Terminal Blocks' page has been expanded to show problems and solutions for damaged blocks as well as work-arounds for blocks that use screws that are essentially unavailable. This will be very helpful if you accept one of these amps for repair and the screws are missing or damaged beyond use.
    • I've updated/expanded the information on several of the class D troubleshooting pages.
    • Of course, I've added new photos of amplifiers that help identify missing or burned components in the amplifiers.

    February, 2007 -- Updated!
    • I've updated and expanded the page showing how to check most common semiconductors. This includes new graphics and more detailed instructions.
    • I've added information on the sizes of the terminal block screws for the most common amps. The information includes diameter, thread pitch and length. For amps that use similar terminal blocks, I've included photos so you can match them up. Many times, the screws used in terminal blocks are not available locally. This information will allow you to order the correct replacement screws the first time (no guessing at the size and thread-pitch).
    • I've included the instructions for making jumpers for the JL 500/1 amp. These allow you to separate the two boards so you can check waveforms and voltages on the components between the boards. Without these jumpers, you have to separate the boards, solder a wire to the test point, plug the boards back in and then take the measurements using the jumper wire. The jumpers allow you full access to the area between the boards.
    • The power supply troubleshooting flowchart has been expanded. It covers more defects and provides more tips to help make the repair more reliable.
    • If you've worked on MTX amps, you've noticed that the power supplies are very different from most other amps. A new section has been added to show the differences (including waveforms). It also tells you how the MTX amps operate differently in the way they switch the PWM drive output on. Much of this information also applies to Sony class D amps as well as some of the Xtant amps.
    • In many sections, I simply showed the schematic symbols for various circuits. Now there are more photos of the components on actual circuit boards. For example, there are about 5 different types of voltage regulators used in various amplifiers. For each one, I provide a photo of the regulators in an amplifier. This will help you to more quickly identify the circuits when you're troubleshooting a problem.
    • The 'Amplifier Basics' page has been expanded including more detail and graphics to help those who are new to amplifier repair.
    • The 'Repair Introduction' page has been expanded. Now there is more information on the ways various components fail and the problems they cause.
    • New links have been provided on many pages to help you find the information you need more quickly and more easily.

    December, 2006 -- Updated!
    • Well over 400 new files and photos have been added or updated since October. The updates on the repair notes include several problems that can be tough to find. At this point, there are more than 3000 photos of amplifier circuit boards (not 3000 different amps). These are very handy when you receive an amp that has missing parts or parts burned beyond recognition. Many manufacturers will not provide any information about their amps so you either have to find another amp of the same model or guess at the values. I've also added two new video clips.

    October, 2006 -- Updated!
    • I've added a page showing many of the common problems and solutions for one of the most common class D amp designs (used by several different manufacturers).
    • More video clips have been added (more than 30 video clips at this time).

    September, 2006 -- Updated!
    • More information has been added to assist in repairing older ('BBQ' pit style amps). This covers a lot of the other Rockford amps also.
    • More video clips have been added.
    • A new interactive op-amp demo has been added to help those who don't understand the various op-amp circuit configurations.

    August, 2006 -- Updated!
    • Recently I've been adding small video clips that show common repair procedures. The following is a partial list of the types of procedures shown:
      • Replacing surface mount components (transistors, resistors and ICs)
      • Removing/replacing spring clamps
      • Removing the types of transistors that are soldered to the insulators
      • Other miscellaneous, but important tasks

    July, 2006 -- Updated!
    • I've added a new page dedicated to helping buyers to understand how a scope is used for quick troubleshooting. The page includes notes on the various test points including what they should see and what to look for if the proper signal isn't present.
    • More than 300 files added, edited or modified this month alone.

    June, 2006 -- Updated!
    • I've added a page dealing with repairing amplifiers that have thermal damage to the circuit boards. Many times, the copper foil traces will be damaged when an amplifier fails. This is very common in the power supply section. This new page takes you through one such repair.
    • A new page helps you to more reliably repair amplifiers that have physical damage. This page tells you how to perform repairs that will produce very reliable repairs. This is especially helpful for single sided circuit boards.
    • I've added a new page that helps you to more efficiently troubleshoot problems in the power amplifier stage of an amplifier. This includes information for troubleshooting inside the feedback loop where discrete differential amplifiers are used.
    • An entire page is now dedicated to the replacement of power transistors that are soldered in place. These are used in amplifiers from Rockford, Pioneer and Digital Designs. The page takes you through a repair where the previous repair was not properly performed. It shows you how to prevent making the same mistakes as well as tips to make the repair as reliable as possible.
    • There have been updates to both the Equipment and Tech Tips pages. Minor revisions have been made to other pages as well.

    March, 2006 -- Updated!
    • The tutorial includes relatively high resolution images of the internals of more than 100 amplifiers. The images can be used to determine the values of burned or missing components or simply to help familiarize yourself with the layouts of different amplifiers. According to a search of the folders with amplifier images (I didn't count them), there are more than 1500 large, high quality images (500kB-1MB per image file).
    • I've now begun to add waveform images for both the audio and power supply sections of both linear and class D amplifiers. Some of the waveforms are an overlay on the schematic. Others point to points on the circuit board (IC and transistor terminals/pins generally). Most of these are in flash format. This allows me to include many high resolution waveforms. You simply zoom in to clearly see the waveform of interest. There are also waveform images that are named so that you know what they are (those are in the folders of the respective amplifier). There are more than 300 waveform images as of now.
    • I've also begun adding more descriptions of repairs and the troubleshooting procedures. Some of the repairs were simple and some were very complex. For those just starting with this type of work, this will be very helpful.
    • For those who do not yet have an oscilloscope, I've added images that show the waveform and the equivalent DC voltages (as they would read using a digital multi-meter). I have values/images for all pins of the HIP4080, the TL494/594 and the SG3525. Even if you have a scope, these are helpful to let you determine whether the waveforms you have are correct or not. Most all of the scope images show the vertical amplifier (volts/div) and timebase (time/div) settings so that you now how to set your scope. Some of the images show the entire face of the scope (and all of its controls). Others show the waveform on a scope that displays the values on the CRT.
    • I've included more datasheets with suggestions for stocking the most common parts. The datasheets included include power transistors (FET and BJT), op-amps, regulators, muting transistors, driver ICs and more. Nearly 100 are included as of now. These can generally be downloaded but it's quicker to grab them from disc than to find them on the internet.
    • A new page helping you to better/more efficiently use your meter when testing components.
    • I've added 2 new pages that help those who are completely new to electronics and/or repair work. One includes descriptions of various components including quick-links to more detailed information (also included on the tutorial disc).

    July, 2005 -- Updated!

    I've added more information to help ease newbies into the technical aspects of the tutorial. I've also updated it to include all of the extra material (test questions, applets and demos) that are included on the full version of the site CD.

    • Protection Circuit troubleshooting with 4 new interactive demos
    • Interactive audio and power supply troubleshooting flowcharts
    • It contains...
    • Troubleshooting basics chapter to help those who are new to electronics including 5 new interactive demos (January 2006)
    • Protection circuit troubleshooting with 4 new interactive demos
    • Interactive audio and power supply troubleshooting flowcharts
    • Audio troubleshooting basics with an image or two of audio waveforms
    • Basic circuit diagrams for different types of output transistor configurations
    • Class D basics with information about the HIP4080 driver IC including:
      • Pin out descriptions
      • Typical power supply configurations
      • Typical op-amp supply voltages for different types of power supplies
      • Drive output diagrams
    • Suggestions for setting up a workbench for repairs
    • Suggestions dealing with customers and reducing headaches when dealing with them
    • Images that show the location of various parts (output transistors, power supply FETs, rectifiers, thermistors...) on various amplifiers.
    • Tech tips and basic troubleshooting suggestions (more than 80 different tips to help you save time, effort and money)
    • Schematic symbols used in amplifier schematic diagrams including:
      • Resistors
      • Potentiometers
      • Diodes
      • Bipolar Junction Transistors
      • N-Channel Field Effect Transistors
      • P-Channel Field Effect Transistors
      • Junction Field Effect Transistors
    • Suggestions for specific tools (desoldering pumps, irons, screwdrivers...)
    • Power supply design/operation basics with actual oscilloscope waveform images
    • A very detailed explanation of the most popular power supply driver IC (TL594) including interactive Flash demos showing:
      • Comparators
      • Error amp input and dead time control
      • PWM comparator operation with 3 inputs (all interactive)
      • PWM comparator operation with 4 inputs (all interactive)
      • Lockout voltage and regulation
    • Tips on getting an amplifier's power supply to come on when the amplifier continually goes into protection (this is very helpful)
    • Basic power supply schematics with 3 different types of power supply MOSFET driver circuits
    • Information about different comparators used in power supply protection circuits
    • Information about thermal protection and the types of devices used in those circuits
    • Links to some of the most popular replacement parts datasheets (including some hard to find datasheets)
    • Common parts package outlines with pin configurations including:
      • TO-218 Transistors
      • TO-220 Transistors
      • TO-92 Transistors (both Japanese and American types)
      • 14 Pin quad op-amp
      • 8 Pin dual op-amp
      • 9 Pin dual op-amp with power feed-through circuit
    • Circuit board layout information including:
      • Foil layout and component orientation
      • Silk screen definitions
    • Internal block diagrams of the 2 most popular op-amp configurations
    • Common op-amp circuits used as buffers, inverting amplifiers and non-inverting amplifiers
    • Information on negative feedback circuits using discrete differential pairs or op-amps
    • Information about 4 different types of voltage regulators found in amplifiers including:
      • Simple shunt regulators
      • Current boost shunt regulators
      • Fixed regulators
      • Resistor-programmable regulators
    • Basic description of 2 types of muting circuits
      • Relay muting
      • JFET muting
    • Information about the generation of higher_than_rail drive voltage for common collector amplifiers
    • Notes on the equipment needed for repairs
      • Power supplies (pictures of both linear and switching power supplies)
      • Dummy loads
      • Voltmeters - The following DMMs are shown on the tutorial.
        • Fluke 77
        • Fluke 79
        • Fluke 27
        • Fluke 11
        • Fluke 112
      • Oscilloscopes:
        In the tutorial, I cover a significant number of oscilloscope features and give quite a few suggestions for buying a used scope. As of now, virtually every feature that you'll need is shown and explained. I even show some advanced features that are not necessary but are available. Some of the scopes were purchased on eBay and for those scopes, I tell you approximately what they cost and/or what you can expect to pay.

    Also included are high resolution images of the internals of more than 100 amplifiers (3000+ images). For someone who isn't familiar with the various amplifiers on the market, the photos will show them what they might encounter. Many times I use them as a reference. If an amp has missing components or components that are burned beyond recognition, I can refer back to the photos to determine what I need to repair the amp. Even if the exact amplifier that you need isn't available, there may well be one that's similar enough to be of help. There are many amplifiers that use very similar circuits. Many times, the only difference is the way it's laid out on the board. The photos generally include one overall image of the amplifier. Then each section (power supply drive, audio drive, preamp...) is photographed to allow you to see the fine details. In general, the resolution is high enough so that the values of tiny surface mount components (often only 0.05" wide) can easily be read.

  • Back To The Menu

  • Cost of the Tutorial:
    The cost is $49.95US. If it only included all of the information listed above, it would be a bargain but it includes far more than what's listed. Since the average labor charge to repair an amplifier is ~$40-$70, it will take very little time to recover the cost of this tutorial. If you have any questions, email me at

    Back To The Menu



    Please read the following section very carefully if you're considering buying the tutorial as a download.

    • This download is almost certainly going to fail if you try to download to a mobile device.
    • The tutorial was written starting 10+ years ago and the format is designed to be used with a laptop or desktop computer with a full size monitor and a mouse. It's essentially unusable on a small display using finger swiping/selecting.
    • This tutorial contains interactive Flash graphics and cannot be used with a modern browser since Adobe and new browsers have seen it necessary to block Flash. There are multiple options for viewing and interacting with Flash content. Some can be found HERE. Basically, it's as simple as using an older browser like Safari 5.1.7 AND Chromium Portable, and installing the old (still working _371) Flash Player files.
    • You should have a static IP address (not absolutely necessary but it can prevent problems associated with the download). If you don't know whether you have a static IP or not, click HERE. Note the IP address. Restart your computer. If you have the same IP address when you check it a second time, you likely have a static IP address.
    • If you don't have a fast internet connection It may impractical to download this file. It's 5GB+ and will take a day or more if you're trying to download it on a slow connection.
    • Remember, burn a copy to a couple of small, cheap flash drives to store backup copies. If your computer crashes (hard drive failure, etc...) and the copy you downloaded is lost, having it backed up means that you'll be able to reinstall the files at no cost.

      Begin Installation Instructions

    • The file you download is a 'zip' file. You will have to unzip that file.

      After choosing to view the files, you will see a list of 4 files (now 2 files and a folder). Open 'index.htm' in your Flash Capable browser. You should already have Safari 5.1.7 and Chromium Portable installed. Other options are available on THIS page.

      The following is what you should see when you open the index.htm file. In the first paragraph (please read all of that page (that was a waste of time typing that)) there is a link to the tutorial's home page.

      This is the page that you will bookmark.

      • The repairtutorial.htm file is the tutorial's home page.
      • You'll want a shortcut to this file on your desktop or make it the home page in the Flash-capable browser that you've chosen to use with the tutorial.
      • I'd also suggest pinning the semiconductor datasheets and the miscellaneousstuff folders to the taskbar.
      • If you regularly go to the Rockford, Kicker, or other folders, pin those as well
      • If you have any questions about this tutorial, email me at

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