I was troubleshooting my RO water filter's UV lamp germicidal purification stage.
The lamps are only expected to last one year, so i replaced the lamp like a few times before but no love this time.
Next i checked the ballast/PS for juice and not only was it hot, but the 44V supply was measuring 120VAC.
The UVc lamp had a weird wiring configuration with what looked like a neon lamp (?) in series with the two heater elements.
The old bulb had plenty of discoloration which is normal over time. The neon (?) lamp was solid black and measures a couple megOhm instead of open circuit like good neons.
Getting back to the ballast, and to practice what I preach I looked for the UL mark... instead I found CE, made in Korea and some cryptic symbols.
The first one I figured out was a rectangle inside another rectangle. This denotes class 2 wiring or double insulated. This should make me feel better except that my VOM measured continuity between each pin of the line cord plug and each pin of the low voltage output connector... so not even single insulated as the 120VAC output voltage measurement suggests.
The other symbol i still can't find looks a little like a trash bin inside a circle, but there is no line through it, so i guess this means OK to discard in the trash? Which I plan to do soon.
[/edit ] I took this apart because I could and the ballast appears to be a simple series inductor, with no pretense of even single insulation, let alone double. So I call shenanigans on the Korean manufacturer. [/edit]