I can't imagine that it would be hard to find any of the parts in today's inverter offerings.
You are obviously not in the electronic repair game, or you would understand the problems a bit better.
Nobody supplies circuit diagrams, the software is an unknowable unknown, many of the electronic parts are now so small, they don't even have any identification on them. If a part is burned out, no way of knowing what it was originally.
Multilayer circuit boards are untraceable, so no way to figure out how its supposed to work.
The manufacturers these days, aim to do several things:
Make it as cheaply as possible.
Build in planned obsolescence.
Never supply information that might make the unit potentially repairable.
Make sure its as difficult as possible to take the product apart for repair, without doing so much damage its then physically destroyed.
Make it as difficult to copy by a competitor as possible by deliberately hiding things by using unmarked, sealed, or custom parts.
Make "special parts" like chips holding proprietary software unavailable as a spare part.
If a unit fails under warranty, give the customer a brand new replacement unit. Its a lot cheaper not to have a repair department at all, and have to employ a lot of extra useless people. NOTHING is made to be easily repaired these days.
All you need are a production facility, sales and marketing and a distribution warehouse.
Technical backup and spare parts inventory are a cost you do not need to have.
The only way to own an inverter that is easily and quickly repairable is to design and build it yourself.
That way you know EXACTLY how it works, and where to obtain every part.
But people just want to buy cheap Chinese stuff, and complain when it stops working after only a few months.
Its all driven by profit and nothing else matters these days.
