bricks n bolts

TUTORIAL Replace bulb on 12v light brick

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I had a whole stack of broken 12v light bricks where the bulb had gone. In particular they don't last that long when set in lamp posts.

Sick of buying more so needed a way of replacing the bulb with a longer lasting LED.

The first difficultly was finding the right LED with a built in resistor so they can run straight off the 12v power supply.

I hadn't found 3mm white/clear LEDs before, just coloured ones, but found a supplier here for what I needed. These should also work fine for 9v.

Then the other tricky bit was to open up the light brick without breaking it. This wasn't as difficult as I first thought, so here is the guide - no soldering and no glue! :tongue:

The tools used (almost common household items!) excluding the light brick and LED are :

1. A micro-screwdriver.

2. A bent curtain hook.

3. Some sharp nail scissors.

photo1.jpg

Step 1.

Using the screwdriver scrape off the plastic tab that helps hold into place the inner part of the light brick :

photo2.jpg

Step 2.

Using the holes for the plug as an anchor lever out the inner part of the light brick with the sharp end of the bent curtain hook until you can get under it :

photo3.jpg

Step 3.

If the inner part is still not loose rotate the other end of the curtain hook in the space made at the bottom :

photo4.jpg

Step 4.

Take out the inner part :

photo5.jpg

Step 5.

Use the micro srewdriver to remove the old bulb and contacts until the inner part is clear :

photo6.jpg

Step 6.

Throw away the old bulb and wiring and Insert the LED :

photo7.jpg

Step 7.

Bend the LED wires around the light brick making sure the LED is centred :

photo8.jpg

Step 8.

With the screwdriver continue to bend the LED wires into the plug contact holes :

photo9.jpg

Step 9.

Re-insert the metal contacts. This may take some force, but it will be this additional friction which means the removal of the plastic tab earlier doesn't matter :

photo10.jpg

Step 10.

Trim off the excess LED wires with the scissors :

photo11.jpg

Step 11.

Re-join the central part of the light brick with the cover (remember which way is up!) :

photo12.jpg

Complete!

Remember as it's an LED it won't work plugged in either way to the power supply, but that doesn't bother me in the slightest as you just turn the plug around / swap the pins if it doesn't work :grin:

For train lights where the power will be reversed when you reverse the train I can recommend Janco's light bricks which are superb

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you should also include a resistor shouldn't you?! 12V 20mA and an LED voltage of ±3V so 11 / 20mA so 9V left, 9V / 20mA = 450 Ω and a good value (E12) will then be 470Ω.

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you should also include a resistor shouldn't you?! 12V 20mA and an LED voltage of ±3V so 11 / 20mA so 9V left, 9V / 20mA = 450 Ω and a good value (E12) will then be 470Ω.

Nope, the LED chosen has a built in resistor. http://www.goodwillsales.com/white-12v-flat-top-3mm-leds-no-resistors-required-prod-2114.html

Good brightness too, I have several of these running now in my lamp posts.

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Thanks for the clear pictures! If you still want to use bulbs instead of LEDs, you can also try these:

- http://www.conrad.co...ment-lamp-Clear

- http://uk.rs-online....-lamps/6559198/

(source: http://www.heinerber...ine.de/tips.htm)

Thanks for the links! I missed those micro-filament bulbs on Conrad. I wonder how they compare with the original Lego ones for brightness and longevity.

Also lots of interesting things on http://www.heinerberg.homepage.t-online.de

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Nice job! My next project after the 12v point motor was going to be the very same...!

I like the idea of LED's because of the low mA draw, but I like to run my lights on the 13V A.C. output to maximise what can be plugged into the transformer :classic: .

I found the same filament bulbs on RS as Alainneke and have them on order.

There's life left in the old 12v ogeL yet!

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Nice job! My next project after the 12v point motor was going to be the very same...!

I like the idea of LED's because of the low mA draw, but I like to run my lights on the 13V A.C. output to maximise what can be plugged into the transformer :classic: .

Thanks, I'm running mine off the transformer D.C at the end plug where all the switches go, don't notice any drop off from there.

There's life left in the old 12v ogeL yet!

Sure is, dont forget to check out my post on how to use PF motors on 12v http://www.eurobricks.com/forum/index.php?showtopic=63535&hl= :thumbup:

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Thanks, I'm running mine off the transformer D.C at the end plug where all the switches go, don't notice any drop off from there.

Kudos where it is deserved :wink: !

I run lights from both the switch 'end' connection and the above mentioned a.c.; you can run 800mA from each...

Sure is, dont forget to check out my post on how to use PF motors on 12v http://www.eurobrick...topic=63535&hl= :thumbup:

Already have! Now I know why I have so much competition on 3bay for the old ogeL 12v track :classic: !

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Sweet mod b n b....thanks for sharing.

LLL

It's really nice of you that you want to thank someone for starting a topic, but please also consider our policy on topic bumping (linked in the Site Guidelines). Thanks. :classic:

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Sorry to bump this topic, but pictures are no longer there. Is it possible to reupload them?

I have two yellow 4,5V light bricks that are not working anymore, and I don't want to ruin these. I even think about upgrading these to 12V.

Is there any difference in manipulmation between the clear lens and the diffuser lens?

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Hi Evans,

Sorry, this is totally my fault, I'm hosting the pictures myself and in the middle of a house move, so server has been offline since Thursday until I can get my line restored.

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Thanks for putting back pictures!

Aren't the LEDs too bright compared to the original bulb? I've recently bought PF LEDs, and I find the light way too bright compared to my 12V and 9V lights.

Anyway, I will try to find such light bulbs to revive and upgrade my broken 4,5V light bricks!

 

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