I am in process of building
Have a working PIC controlled soldering iron that has an LCD display.
Just getting the little bugs out and adding an auto shut-off.
In my book if it doesn't say HAKKO it has little chance of being a genuine HAKKO
The PIC controlled with zero crossing (another add on I am hoping for, could be build for under $30 less transformer.
The iron off Ebay = $12, PIC = $4, LCD = $4, could be built on a perf-board.
The HAKKO schematic I found on the web turned out it had problems. Missing connections etc.