For those with my tutorial

When was the last time you updated?

Service mode isn't likely the same for all of the amps. Many have bridges that are opened to break the feedback loop or to prevent the MCU from shutting the output stage down. Is there something else you're seeing?

Brazilian/chinese clones?

Do you have specific makes/models in mind?
 
It costs nothing to stay up to date. There are daily changes in the content. I don't know what's in the 4 year old version but if you get the newest version, I may be able to point you to sections that may answer some of your questions. Email me if you want to DL the latest version.
babin_perry@yahoo.com

You can't use current browsers since they no longer support Flash content. Read through the top section of the following page for the software you need to have installed.
https://www.bcae1.com/temp/!_READ-ME_if_you_want_to_view_the_Flash_files.htm

No one will read the following part of the intro page because it's boring and not technical but it's important. This is a static PDF version so the links won't work but reading in this format is better than ignoring it completely.
https://www.bcae1.com/temp/pleasereadintro02.pdf
 
Hey Perry,
Haven't read your tutorial, but the last section in your link (the one you think no one will read - lol!) is right on point. Don't let your desire to help someone become your problem (said differently). We've all tried and suffered for it.

This can be said for all equipment. If there isn't support, walk away. The best thing you can do is explain this to the customer and let them make future buying decisions based on that.

Big hint: "repair by replacement" means there is zero support. Out of warranty it is the owner's problem. OFten they want to sell you the current model, you pay extra or are offered a discount.