Hello,
My father-in-law bought some "icicle" lights last Christmas. He has come to use them this year and some of the icicles are not lighting, so he's given them to me to fix.
I don't know the make or model for sure. The label on the lights says "Konstsmide", so I am pretty confident that that is the make, yet the transformer says "Premier", a rival manufacturer. This could be the reason they have blown: he could be using the wrong transformer! I've emailed both companies and we will see if they reply.
There is a chain of plastic icicles and inside are up to six tiny filament lamps which light with the usual filament yellowish white. A section of sixteen bulbs is not lighting up; the rest work perfectly. The lights are always on: there is no flashing, sequencing, etc.
The (wrong?) transformer says it has an output of 24V AC. Since the working bulbs look "about right", I think that even if the transformer is the wrong one, by coincidence it might be outputting the correct voltage.
I have dismantled the icicle "lamp shade" and found a blown bulb. If I short this out, the other fifteen bulbs come to life. If I put an ammeter in its place, it reads 68mA AC. So far, so good.
It's a while since I was at school, so can someone just double check my maths: 24 Volts across 16 bulbs, would mean the voltage across each bulb is 24/16=1.5V. Is that right?
The reason I hesitate is that I have searched electronics catalogues and I cannot find any filament bulbs rated at 1.5V.
I don't want to just short the blown bulb because that will cause the current through the other bulbs to be 16/15ths higher and that in turn could cause more to blow. If I've got my maths right, the resistance of each bulb is twenty-something Ohms, so I might put a 22 Ohm resistor in its place if all else fails.
Does anyone know of a source for these tiny bulbs?
On a similar note, SWMBO wanted to follow the family tradition so we bought LED lights. The first year two sets went back because rain got into them. There is heat shrink over the LED and series resistor and you could see through the heat shrink that there was rust. We bought a different make last year but one or two LEDs are not working on that; again rust seems to be the problem. So much for LED lamps not needing replacing!
Thanks, Stephen.