If you find LEDs that blink to fast to suit your taste, you can slow them down with some simple circuit modifications. The actual procedure you will need to follow depends on the circuit design that controls the blink rate of your LEDs. Most circuits use resistors to control LED blink rate. Once you find where the resistors that control the blink rate are located, you can adjust the resistors' value for a slower blink rate.
Obtain the schematic of the LED flasher circuit you want to stop the LEDs from blinking too fast. Locate the resistors on the circuit schematic. Look for any notes on the schematic that may give you a clue as to what resistors control the blinking rate. Write down the values of the resistors that are on the schematic.
Open up the LED flasher circuit so that you can see the components that are in the flasher. Locate the resistors on the printed circuit board. Read the values written on the resistors and match them to the resistors on the schematic.
Attach a variable resistor to the right and left leads of one of the resistors on the circuit board. Turn on the flasher. Adjust the value of the variable resistor with a small screwdriver and observe whether or not the LED blinking rate slows down with the change in resistance. Remove the variable resistor and attach it to the left and right leads of another resistor. Continue in this fashion until you locate the resistor that controls the LED blinking rate.
Some circuits use a voltage to control the blink rate. The blink rate of the LED can depend on the value of the voltage on the pin. Sometimes two pins control the blink rate. For example, if one pin is at 5 volts and the other is at 0 volts, you will get a slow blink rate. On the other hand, if the pin voltages are interchanged, you will get a fast blink rate. It is always a good idea to get the data sheet of the components in your flasher before you attempt to outguess the functionality of the components.
Not following proper safety procedures when working with electronics may result in serious injury or death. Always work under the supervision of a trained electronic technician or electronic engineer when you work with electronic equipment and devices. Take a electronics safety course before you begin working with electronic components and devices.