DIY Doctor UK DIY Forums

Hello
Stupid Question time

I have just purchased a new Christmas Tree in the sales, it is a fibre optic tree with twinkling led's on the ends of branches. When I turned it on, the light that makes the fibre optics light up is perfect, none of the LED's work though. I have been refunded for the broken tree but thought I might see if I can fix it ( i was given the option to use or dispose of it as I want to). after initial inspection I carried out some checks, the PSU is supposed to put our 12v DC, it does this, and the output socket for the LED's also has a 12v DC supply. I then noticed that the flasher box is a 24v Flasher box - simple question really, could the fact that the flasher box requires a 24v, the tree base only provides 12v be the problem, or would I still get dim LED's from 12v? ( all the output pins on the flasher box have 12v across them.

Thanks in advance

I just noticed this did not get a reply, did you get the problem sorted, or will you be panicking in September?

It is an interesting question so lets start.
1) It would seem strange to use a 24v unit that would not work with 12v as every tree would have been faulty.
2) LED's are unlikely to be 12v or 24v most LED's depending on colour are around the 1.2v and really are more current than voltage dependent. There are two basic ways to reduce from 12v to required voltage.
a) A simple resistor if this is method then likely LED will work but dimmer.
b) Integrated circuit which often is a switch mode power supply with this they can often have a huge variation in voltage without any change in LED output.

The problem with these units is often the chip that does the work is encapsulated and there is nothing one can do other than bypass it. Then the question is will the power supply work all lights together or will it be overloaded?

Like you I love to play with things like this but normally they end up in the bin at the end.