I have a use for one of these all new unused in 1990s, not stored in a
shed or garage over the years. A few dozen ,made in 1992 nice compact
70W Electronic Halogen Transformers (so called including labels as
primary and secondary on the external label). Outputs the unrectified HF
to drive the 12V lamps. They used to work 15 years or so ago. Now I've
tried 3 and all the same , should be 12V HF ac and if attached to high
speed diode and a cap and no load then only about 10 to 12V dc. No way
will they power even a 20 W lamp (supplies are rated 20W to 70W) tried
40W in case load dependent. Scoping, with no load and a complex
oscillation signal. Then as little as 27R load very poor mark space
ratio of output and fraction of a volt as DC. These units are potted
with that white hard-rubber-like stuff but I have one that I excavated
out a lot of the fill and that is the same fault. No green corossion
stains or oil films seen associated with any components still in the
fill (only removed enough to check what components were in there.
Philips EHC 070 S/40 , no controller IC , 2 STL57 driver transistors and
the small componentry as SMD on a small daughter board. Stable 350V on
the rectified mains caps, polyester, no electrolytics at all in these
units. Transformer is good up to 1Gohm on insulation test. Fuse and
thermal fuse in the exposed one are good andother stuff cold test ok