Odd Issue - LEDs dimming after a month of use
New to electronics I've started added lights to some model kids I've been working on, and one is having a problem unique enough that google thinks it's a handful of other problems.
I wired a model with LEDs and after a month they are less bright. I wired in a new set two months ago, full brightness, and they're back to being so dim I can barely see them.
- Power supply is 12V 1amp, plugged into a remote on/off switch into a wall outlet (US). I have changed power supplies once since I initially thought it might be the culprit. When I replaced all the dim LEDs I also changed to this new power supply.
- There are two types of LEDs, the model base has five [ultra bright LEDs](https://www.amazon.com/dp/B08GSMS6H2) pre-wired for 12V, I wired them parallel. They are not enclosed, they poke through a thin plastic base and then are then open air.
- The second set are [mini LEDs](https://www.adafruit.com/product/5487) are wired in series with a 300 ohm resistor, and are connected to the power supply is parallel with the other LEDs. These are in an enclosed space.
- All connection are soldered. Large LEDs use only the wires already provided with them, small LEDs are connected with a 30 AWG ribbon cable.
I'm sure the problem is simple and I've been one or two forum posts away from the solution, but so far it has escaped me. Sorry I don't have a wiring diagram, but at this point I'm worried I'd draw it wrong and add confusion.
Model is Nilson Works Monument Repair Type in case it comes up
