The modifications depicted on these
pages are solely my own applications and if you want to try them, you do it at your
own risk. I cannot be held responsible for any damage or mishap.
First take a normal bulb. Measure the length of it. It is approximately 38 mm. This is standart and you don’t need to measure again.
Remove the both metal ends (whatch your hands because the glass breaks easily). Throw away the glass and the filament. Scrape the inner surfasec of the metal ends to remove the cement-like material.
Take a universal circuit board and cut it to the dimensions in the picture (count the holes!). The exact figure is 28 mm by 8 mm.
Get four 3mm LED’s. Note that the LED’s have two pins of different length. The longer one is the anode which must be connected to the positive supply. As the white LED’s have a forward voltage of around 3.6 V you must use 4 of them in series. When you start the motor the board voltage will increase to 14.4V. (3.6 V * 4 = 14.4 V. Interesting?). Now, place the LEDS on the board. Take care to the polarity.
You can use a helping hand stand and some drops of cyanoacrylate glue to fix the LED’s in place before soldering.
Cyanoacrylate glue or hot silicone. Not too much!!
Now the
soldering...
The outer pins of the first and the last LED must be bent at 90 degrees. The other pins will be cut after being soldered to the corresponding pin of the neighbouring LED.
Now test the assembly. If you soldered any one of the four LED’s in reverse polarity, the whole assembly is obsolete. Just test it!
Now the final assembly. Heat the ends of the metal caps with your soldering iron and stick the LED pins through the holes. Then solder the pins to the metal caps. You can use some hot silicone for added mechanical stability.
When installing these new bulbs you must try them in both positions because if the polarity is not correct the bulbs will not light up. The reverse voltage tolerance of a white LED is 5 V and for four LED’s in series reverse voltage can be as high as 20 V. That means, you cannot harm your new LED-bulb if you install it in the wrong direction. You can just change the position and it will light up.