The industry has seen an influx of electronics not only built in China, but designed and marketed by apparently offshore companies. Many of these items are pretty difficult to obtain parts and/or service manuals for (a problem not limited to offshore manufacturers).
I recently had to deal with a Centurion CS3000 45 amp converter/load center which was working, except the cooling fans would not run. A quick check of the fans (typical computer type “muffin” fans) said they were good, they just were not getting any power. Normally this would require the replacement of the converter, but after a few minutes of research, it appears that this is no longer available (a part that’s only a few years old).
Even though I am not an electronics tech, I do have a small bit of experience, so I pulled the circuit board out of the converter and had a look. At first glance, it looked like the fan was controlled by a simply thermal switch- but… not so. The thermal switch which is attached to one of the heat sinks instead is an overheat switch to shut off the entire converter, and the fans are controlled by a special circuit- apparently tied to the current draw on the converter.
Tracing the circuit a small bit led me to a pair of transistors which had that “overheated” look to them- the circuit board was a bit discolored underneath.
Given that I had another identical board (which was destroyed by hooking a pair of 12 volt batteries up incorrectly- 24 volts- and had some catastrophic failures- parts splattered across the board)- I pulled the 2 transistors off of the second board, and installed them on the first one.
Result- a good, working converter.
It is hard to find qualified electronics people in the RV service industry- and I don’t claim to be one- but many of these converters (the thousands of Todd converters come to mind) can probably be repaired by spending pennies on parts. Now whether it makes sense to pay a technician to figure out the circuit (without schematics) and then do the repair is debatable, but it is possible.