Yep - born & raised Dutch, but now Californian resident.
Clarification for others not familiar with the term - Elco means Electrolytic Capacitor. I was not aware that it is a typical Dutch expression.
Re: isolated, I referred to the housing, indeed the electronics are "hot" so it is required that it cannot be touched anywhere, including at openings for trimming pots to select sensitivity and timeout of the PIR detector. Unfortunately that are typical locations where (rain)water gets in, causing the demise of the detector. Usually it first starts acting weird, switching the light on and off randomly before finally failing completely.
"geisoleerd" is indeed the Dutch word for "isolated" and essentially means separated, so this can mean either the galvanic isolation from the grid or the protection of a "hot" circuit from touch by a non-conducting enclosure. So a further qualification is needed and I forgot to re-read my typing so I did not catch that my statement was ambiguous.
Most likely you found the same type of rope light that I had a section fail in.
I just modified the lamp from Amazon. The head is almost identical to the one in the video, but the design of the weight and the ballast coil in the base are different. You have a lot less room to work in the new base, but because the electronics is so simple and produces no heat, I was able to do it. Amazon is currently out of the lamps, but will email me when they come in. I'll keep this blog apprised. Then you can email me for a photo and a layout drawing of the new circuit board.
If you use a zener diode as the voltage reference instead of an LED, put a forward-biased signal diode like a 1N4148 in series with the zener diode to block a sneak-path that slows down the startup of the circuit. The LED would be back-biased during start-up, blocking the sneak-path. Note that this turn-on delay might not be noticeable unless the electrolytic capacitor is discharged. It does not have a bleed resistor, so it can hold a charge for days, once the voltage has dropped below that required for the LEDs to conduct.
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