12.01. Bulb to Diode

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Bulb to diode

Tip from Clay Lubbers.

Changing an XS650 stock bulb to a diode.

Swapping the bulbs in the indicator lights and the gauge lights went great. The LED's, as Goran said, are a little dimmer for the gauge lights, but they *rule* for the indicator lights (such as bright, neutral, turn signal indicator, etc). I found a better way to mount the LED's though. After doing a couple like Goran recommended, I tried something different and it worked better.

First, I bought all the LED's (I bought superbright ones- total-$16.00) and 1/2 watt 560 ohm resistors (total- $1.50) from allelectronics. The total was like $20.00 for *all* the parts with extras (I also bought some different colors- my Tach has blue gauge lights now). Here is the method I used, and the one I would recommend:

Bulb with smashed globe
Cleaned bulb base
Pulling out the base wire while heating

Prepping the bulb base:

Pull out the old light bulbs, and use a pliers to smash the bulb globe (not the metal cylinder!). Next, using the pliers, *gently* compress (so as not to permanently deform it) the metal cylinder until the glass insert (bulb remains) come loose. You will find a small glass bead with the positive and negative wires running through. Pull this out. One wire is soldered to the top (bulb side) of the cylinder- grab this and pull it off. The other runs into the soldered base tip of the bulb. Now here's the pinch- take your soldering iron and put it on the outside base tip of the bulb. You will soften the lead enough that you can pull out this wire without ruining the base. You now have prepped the bulb base. Set it aside for later.

Soldering the resistor to the LED. Note the bend in the wire.
Soldering detail

Prepping the LED:

Take the diode and figure out which end the resistor goes on. If you look *closely*, you will see in the diode there are two leads- one larger, one smaller. Solder the resistor to the lead on the *smaller* side of the diode. Attach the resistor with the side that has the stripes that are close together *away* from the diode. This is the positive lead of your diode. I had to play around with it and a 12 volt source for a bit to figure out which side of the diode goes to which side of the resistor, and this way worked for me. Cut the resistor and the diode leads to about 1/8 inch (or about 2-3 mm for you metric fans), overlap them and solder them together. Evidently they both are rather heat resistant, because the proximity of the hot solder did not hurt either of the electronics. Now, take the unsoldered lead of the diode and put in an elbow to spread the leads apart a bit.

Note: It dose not matter which way around the resistor goes but get the LED around the wrong way and it could blow it! The long lead is the Anode which goes to the Positive + and the short Lead is the Cathode which goes to the Negative -. It dose not matter which side of the LED the resistor goes but conventionaly it is on the positive side on a negative earth vehicle. (xs650@hotmail.co.uk)

Checking the length of the LED leads
The final fit. Now heat the base (like before) and press the wire through and solder the negative lead.

Attaching the LED to the bulb base:

The idea is this- you will use your soldering iron to heat the base of the bulb to soften the lead and slide the resistor terminal through it. This will give you the positive connection for the circuit. You take the other terminal and solder it to the rim (top edge) of the bulb base. You'll note that along on part of the rim (top edge bulb side) of the bulb base there is a bit of solder where the bulb terminal was attached. This makes a great spot to solder the negative terminal. If you bent the terminals and cut the them to the right lengths, once everything is soldered the LED is about the same height as the bulb. You have now created a LED light that uses the bulb base- simply plug it in and you're good to go.

It took me a bit to figure out the method (I'm not sure my explanation is clear enough here), but once I did I was building them about 1 every 5 minutes, and they work great, plus there's no bulb socket modifications to make.

Thanks Goran- your plans worked *wonderfully*! It's great to have gauge and indicator lights (they weren't working when I got the bike). This may sound complicated, but it's not. Any guy with a modicum of patience (and you're getting that from an adult with ADD!) can do it. My soldering iron is one of those $5.99 units, and it worked fine for the task.

Good luck! If you have any questions, email me at mailto:ClayL<at>altelco.net ClayL<at>altelco.net.


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