Thanks for some good teardown pictures. And good timing as I also was thinking of buying one from US, although I'm in Japan. Less than half price in US compared to here!
The problem is that US have 110V while Japan have 100V. I hope there are taps on the trafo for 100V. Should be as it seems that Hakko only has two type of trafos (seen in this pdf http://www.hakkousa.com/AHPDirect/download/UM/FX888e20100831.pdf). Or I'll just leave it.. I have measured mains to 105V at home so it should work ok I guess.
I don't think 10V is much of a difference. In some rural areas in 110V countries, voltage goes down to 100V. I have heard cases here where it goes as low as 76V! I get 117V consistently. 94V between Live and Earth. Some installations just connect Neutral to the Earth in both points of a circuit so save a cable.
The result is unstable voltage that changes with the conditions of the (physical) ground. Now I have confirmed my home has a proper mains connection. This is something not all houses have, unfortunately. Thanks to incompetent engineers looking to save money on a ground cable, people wonder why their fridge shocks them and they have to get the computer repaired for the same problem every 6 months.
Warning: the following paragraph is a rant on Earthing and safety.A month ago I discovered one of the rooms at home has a terrible installation. So bad I could do my own being an electronics hobbyist with no previous experience in wiring houses. The room was built after the house, so it was kind of an expansion. The idiots took a neutral wire from the next room and they had the live wire directly from the energy meter. They installed a breaker box outside the house, on a *second* floor, outdoors, no protection at all (I seriously doubt that box is waterproof) and wired the thing to the inside. No Earth wire at all, not even shared between the outlets but ungrounded, there was nothing. They didn't even cared about wiring the thing for somebody to ground it. The result is a very nasty voltage on the computer's power strip. They actually wired a second Live line from another breaker in the breaker box and leaved it like that. If they used the money in that wire, why did they used it on something that didn't have any use at the moment? They did it so they can say "oh, now you have a separate circuit, so you can plug more things". Those things will shock you, of course.
Ivan