I purchased one of these recently, because I've got a DIY VNA that is supposed to have extremely high dynamic range if powered with a decent supply, and I wanted to build a linear PSU for it with as much filtering as I can reasonably manage. It arrived the other day, I still need to use it.
From a quick initial examination, the outer metal band (copper?) is electrically connected to the stamped metal base. Both are lacquered I scraped at that to do that test.
The yellow/green earth wire is not electrically connected to the outer band or the stamped metal base.
The area where the wires disappear into the transformer looks a bit unusual; it is very hard to tell how they have done it because there seem to be some "elements" of construction (hopefully just for mechanical support, but I cannot tell) between the two bobbins. EDIT: There is an
R core transformer discussion that mentions that the primary may be across both bobbins, and the secondary could be across both bobbins.
I will measure capacitance (I think by shorting all the ends of the primary winding, and shorting all the ends of the secondary winding) and then measure between that, and also measure each shorted winding to the yellow/green earth wire too, and to the metal base.
EDIT: Now measured (all primary wires were shorted, and all secondary wires were shorted). Measured in the range of 200kHz down to 100 Hz:
Pri-Sec: 97-99 pF
Pri-Yel/Grn: 99-100 pF
Sec-Yel/Grn: 290-300 pF
Pri-Band/Base: 83-90 pF
Sec-Band/Base: 84-88 pF