I can say with 100% confidence that under the metal shielding inside the 326, you can place a jumper to set the voltage from anything between 110 and 240 Volt 50 and 60Hz.
So you do not need a dealer or anyone else to assist you.
I am almost sure you can do the same with the 436.
As for the 390 I do not know, but I would be very surprised if it would be different from the other two.
So you do not need a dealer or anyone else to assist you.
I am almost sure you can do the same with the 436.
As for the 390 I do not know, but I would be very surprised if it would be different from the other two.