Just goes to show the practical value of a schematic diagram. Just one problem. Contraband products built out of sight from the authorities just don't always come with a diagram. And even if it did, a schematic would seldom get passed along when the amplifier changes hands down the line.
The price of hiring someone to trace down the circuit and draw up a schematic would be enough to buy a few cases of these when they were new.
One back door is to find an identical unit that hasn't been damaged by excessive drive power yet, and copy the markings from undamaged parts.
But those are the three options I see, an original diagram, or have one made, or copy directly from another unit of the same type.
Welcome to the information age. Sometimes the information about a product is worth more than the product itself.
73