HID Center Dead Spot Fix
by someazn » Mon Oct 13, 2008 11:56 pm
Disclaimer: By following this tutorial, you understand that modifying your HID bulbs will void all warranty and may cause irreversible damages. The original poster is not responsible for any damages that may occur by following this tutorial.
The other day I installed new bulbs on my car because I wanted a little more color. Upon installing my new bulbs, I noticed the dreaded dead spot that a few members here have mentioned. I did not have this problem before, so I knew there must've been something wrong with the bulbs. I searched the forums and hidplanet, but found no solution on how to fix this, so I took it upon myself to devise a solution and here it is:
For those of you who don't know what the dead spot looks like, here's a picture I drew in paint representing the light output you would see on the ground. The green portion is visible light, and the red portion is the dead spot. This is what you would see from inside your car:
Now if you look closely at the drawing, the straight lines running diagonally comes from the return wire of the bulb. This is what is causing the dead spot. Since the lens on the projector is ridged, the dead spot becomes more pronounced due to shadow overlap. Had the lens been clear, we would only observe two straight diagonal lines.
Below are two bulbs that give remarkably different results inside the projector. The bulb on the left does not produce the dead spot while the bulb on the right produces the dreaded dead spot. I have positioned the bulbs in the picture so that this would be how the bulbs would enter the socket on the projector. Notice that the bulb on the left has the return wire facing down while the bulb on the right is facing up. (In OEM applications, the return wire would sit at the 6 o'clock position rather than 8 o'clock. Rebased bulbs suck!) Sorry for the blurry pictures.
Now let's have a look at how the bulbs sit inside the projector. For reference, we will call the bulb without the dead spot bulb A and the bulb with the dead spot bulb B.
Bulb A inside projector:
Bulb B inside projector:
Notice that in the first picture, the return wire is facing down and below the cutoff shield. In the second picture, the return wire is clearly sitting above the cutoff shield. The return wire is sitting on the upper left hand corner, so how is it producing a shadow in the lower right corner? Well, with optics, everything is reversed, so the dead spot would indeed be in the lower right hand corner.
Okay, okay, enough with the science crap, I want to modify my bulbs already.
Things you'll need:
- 60 grit sandpaper or hand-held dremel
- Patience
- An extra set of projectors would be really helpful
Estimated Time of Completion: 45 minutes per bulb with sand paper, 10 minutes per bulb with dremel
Here's a picture of the socket holding the bulb:
What we're going to do is we're going to modify the bulb in such a way that the bulb will rotate one tab clockwise. So tab A would sit in tab B, tab B would sit in tab C, and tab C would sit in tab A.
Here's a picture of the bulb with markings showing how it would sit, unmodified and how it should sit after modification:
In order to accomplish this, we are going to have to sand all three tabs. Since the base is not a perfect circle, the entire base has to be sanded as well. Do not shave off too much. The bulb should still sit in the socket securely after this mod. Do this step SLOWLY. Patience is key! Here's a picture of what needs to be shaved off, in red:
Here's what the bulb should look like after sanding:
Now inserting the bulb, as described earlier, rotating one tab clockwise, the bulb should be seated in the projector like so:
Notice how the return wire is now sitting below the cutoff shield.
Unfortunately, I do not have any pictures of how the modified bulbs look on the car (will get pictures up soon though!). But what I did notice was that the dead spot was gone and it was a lot brighter. The return wire caused a significant loss of light. I can see so much better now
McCulloch Ballasts with 6000K Retro-Solutions bulbs.
Here's a reference on bulbs I have tested. Letters indicate grade with A being the best and F being the worst:
Bulbs with dead spots: McCulloch (F), Retro-Solutions (A)
Bulbs without dead spots: VVME (C), XenonDepot (B)
Well, I hope that helps, any questions feel free to contact me.
The other day I installed new bulbs on my car because I wanted a little more color. Upon installing my new bulbs, I noticed the dreaded dead spot that a few members here have mentioned. I did not have this problem before, so I knew there must've been something wrong with the bulbs. I searched the forums and hidplanet, but found no solution on how to fix this, so I took it upon myself to devise a solution and here it is:
For those of you who don't know what the dead spot looks like, here's a picture I drew in paint representing the light output you would see on the ground. The green portion is visible light, and the red portion is the dead spot. This is what you would see from inside your car:
Now if you look closely at the drawing, the straight lines running diagonally comes from the return wire of the bulb. This is what is causing the dead spot. Since the lens on the projector is ridged, the dead spot becomes more pronounced due to shadow overlap. Had the lens been clear, we would only observe two straight diagonal lines.
Below are two bulbs that give remarkably different results inside the projector. The bulb on the left does not produce the dead spot while the bulb on the right produces the dreaded dead spot. I have positioned the bulbs in the picture so that this would be how the bulbs would enter the socket on the projector. Notice that the bulb on the left has the return wire facing down while the bulb on the right is facing up. (In OEM applications, the return wire would sit at the 6 o'clock position rather than 8 o'clock. Rebased bulbs suck!) Sorry for the blurry pictures.
Now let's have a look at how the bulbs sit inside the projector. For reference, we will call the bulb without the dead spot bulb A and the bulb with the dead spot bulb B.
Bulb A inside projector:
Bulb B inside projector:
Notice that in the first picture, the return wire is facing down and below the cutoff shield. In the second picture, the return wire is clearly sitting above the cutoff shield. The return wire is sitting on the upper left hand corner, so how is it producing a shadow in the lower right corner? Well, with optics, everything is reversed, so the dead spot would indeed be in the lower right hand corner.
Okay, okay, enough with the science crap, I want to modify my bulbs already.
Things you'll need:
- 60 grit sandpaper or hand-held dremel
- Patience
- An extra set of projectors would be really helpful
Estimated Time of Completion: 45 minutes per bulb with sand paper, 10 minutes per bulb with dremel
Here's a picture of the socket holding the bulb:
What we're going to do is we're going to modify the bulb in such a way that the bulb will rotate one tab clockwise. So tab A would sit in tab B, tab B would sit in tab C, and tab C would sit in tab A.
Here's a picture of the bulb with markings showing how it would sit, unmodified and how it should sit after modification:
In order to accomplish this, we are going to have to sand all three tabs. Since the base is not a perfect circle, the entire base has to be sanded as well. Do not shave off too much. The bulb should still sit in the socket securely after this mod. Do this step SLOWLY. Patience is key! Here's a picture of what needs to be shaved off, in red:
Here's what the bulb should look like after sanding:
Now inserting the bulb, as described earlier, rotating one tab clockwise, the bulb should be seated in the projector like so:
Notice how the return wire is now sitting below the cutoff shield.
Unfortunately, I do not have any pictures of how the modified bulbs look on the car (will get pictures up soon though!). But what I did notice was that the dead spot was gone and it was a lot brighter. The return wire caused a significant loss of light. I can see so much better now
McCulloch Ballasts with 6000K Retro-Solutions bulbs.
Here's a reference on bulbs I have tested. Letters indicate grade with A being the best and F being the worst:
Bulbs with dead spots: McCulloch (F), Retro-Solutions (A)
Bulbs without dead spots: VVME (C), XenonDepot (B)
Well, I hope that helps, any questions feel free to contact me.
Last edited by someazn on Tue Oct 14, 2008 10:12 am, edited 1 time in total.
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someazn - SolaraGuy Supporter
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