I've connected the LED diode to a 1K resistor. When I tested it out on a breadboard it worked fine, the LED was very bright. Now, when I soldered it to the board, the LED light is poor. The connection is the same, with no changes. I don't know where is the problem. Everything else works fine, so that means the connection between components is good. Could the problem be in the tin or paste I use? Does anyone have an idea?
Btw, everything is connected to a 5V power supply. I measured voltage in some points on board, and it is about 4,65-4,75V. What else can I do to find an error?