I was changing some light bulbs at my mom's house and I noticed that a (water resistant) LED strip she has had turned stiff and almost black. As expected, it hardly gave out any light. The LEDs seem to be working so I think the reason it's hardly giving out any light is the decoloration of the insulation which was once transparent.
I also noticed its power supply (230V -> 12V, 5A) was buzzing and was quite hot to the touch. The strip is about 2m with LEDs every 5cm, so approximately 40 LEDs. Although I don't have a datasheet (since it was installed many years ago by someone else), if we assume each LED to be drawing 50mA, it adds up to 2A - way bellow the 5A of the power supply. Even if they use up 100mA, which does seem a bit much, it would still add up to 4A which should still be fine for the power supply but might explain the heat.
Could the LED strip turn black because of normal use/heat or should I have a better look at the power supply? I didn't notice any obviously busted electrolytic caps with a quick inspection (the top is full of venting holes so I could look inside) but there could be ones where I couldn't look without disassembling it.
I did notice a trimmer on it but I didn't have a multimeter with me to test the output voltage so I have a suspicion the output is somewhat larger than 12V but not enough to blow the strip instantly.
Last bit of information that I found odd but it could be nothing, the electrician had used a 5 core piece of cable, using 3 of them (blue, brown, green/yellow) to connect the power supply to mains and the remaining 2 (blue and brown) to go back and connect to the LED strip. So you have 230V and 12V running through the same cable. Could this have anything to do with it?
I will go back with my multimeter so I can find out myself if the power supply is not set correctly or acting up.