Bluecold beat me to it! We spent some time discussing this with a friend who retired from a career in electronics and he made this all quite clear. The diode does not convert AC to DC, yes, but it creates a circuit where the current is flowing in one direction only, as in DC.

The diode, he explained is a gate or a one way valve, and in AC the current is constantly changing directions in the circuit....visualize a sine wave with the line oscillating above and below the horizontal line and the area isisde the wave represents the power. The diode , as a one way valve, removes the wave below the line, leaving only the top half. Therefore the power, in watts is one half of the maximum although the voltage and current remain the same.

So on minimum, the diode is in the circuit and the element is producing 375 watts. When you switch to maximum, this switch creates a shortened circuit and removes the diode from the circuit and wattage of the element is 750. His opinion from the wiring diagram is that you simply need a new diode to replace the old one and the machine should have the I/II function as before.

Another note learned today is that we in North America often confuse European 220V. Here, 220v is wired by using 2 110v wires and a ground, both are hot wires. In European 220v the 220 is delivered through one wire, the second is a neutral wire, and the third a ground. So a 110v machine and 220v machine are wired the same way with a hot and a neutral wire.

This has been a very interesting topic, and I do think that by using a diode as in your machine that one can adapt the cheaper single coil element to work in a two element machine at half the cost. It is worth further thought and study!

Dear Doug, thanks for the note on the function of the diode, which was also suggested to me from another source. I have now removed it and tested the function using my multimeter. It does seem to allow current in both directions, suggesting that it would be defective. When I get the new diode I have ordered, I will put it back and hope for the best. I promise to post the result of my repair in due time (the diode seems rare enough for my local supplier to have to order it from abroad!). Thanks to all coffee-lovers for useful input and for a most interesting discussion, even though it did involve coffee-making at all!! /Petter Höglund

Did this machine blow steam out the safety when it was at brew temp the way the older massi/minni pavs do.
If so I have a suggestion.
As it has only one element don't bother with the all the mumbo jumbo. A pav with a single element will make a perfectly good coffee. I rarely used the mini setting on my older pav. I turn it on massi run it up to temp, turn off, pull shot, and if I want milk turn it on again, steam milk. I developed this technique when the massi switch stopped working (again! this was the second one to fry, they are underbuilt) and as I was on a trip I just switched leads so that the mini position powered the large heating element. Didn't bother changing anything afterwards because honestly the mini setting is almost the same as turning off the pav and just turning the pav on for half of the time had the same results.
If the weird stuff you have there is some kind of thermo the turns the element on and off, you could still bypass it all, install the appropriate massi/mini safety valve assembly and run it as a massi/mini. If you want to have fun after that, install a gage.
Just my 2 cents....trying to keep it simple, the whole reason I have pavs in the first place