Convert Desk Lamp to Led Bulb.




this tutorial apply mostly to old 12v desk lamp with a G4 or GU4 socket but can be applied to other lamp and defective or damaged integrated led lamp with minor change.NO soldering skill required,but a minimum knowledge in electricity is needed.

in September 2018,halogen light-bulb will be banned in Europe.

most led light bulb will be a drop in replacement for main halogen lamp (g8,g9,gu10,e14...). but for 12v lamps (g4,gu4...)the replacement will not be as straight forward, there is a lots of chance your lamp will not be compatible,buzzing,flickering,burning most led in very short time.

this is because most of those old lamp use a old style of electric transformer,not compatible with led .

most of those old transformer was made for halogen bulb,they are too strong to drive a led,and led don't like the ac they output.(and do not trust the ac/dc rating of those 12v led bulb)

those old and huge transformer are generally inside the lamp base.

if your lamp have a electronic power supply with a metal or concrete weight.your lamp will probably not need to be converted,and led light bulb will work.

this simple tutorial will explain how to modify your old lamp to work with those new light bulbs.

Step 1: Stuffs Needed.

here the stuff needed to modify your lamp to be compatible :

  • a modern electronic DC power supply preferably integrated to the plug. 12v 2A and able to handle low loads (200ma) (2a will handle loads up to 20w,they are very common,had one from a dead router)
  • a power switch (if the one of your lamp is not working,stuck or if you plan to not use the one of the lamp)
  • some way to connect the wires together (wire joiner).
  • the replacement 12v led light bulb of your choice that fits your lamp and needs.

Step 2: Conversion Steps:

the conversion will be easy and dont ask a lots of work.

note we chose to use 12v instead of main power mostly because those lamps are not made to support the main power ,and so we will keep a low voltage in the lamp.

  • step 1: remove the wall plug of the lamp.(it can be cut)
  • step 2 splice the wires of the dc 12v power supply.(this is because we don't want to put main power in wire and a socket made for 12v)
  • step 3 hook the dc 12v power supply to the lamp. (the on/off switch can be used for that.)
  • step 4 open the lamp base and bypass the AC 12V electric transformer. (this is because led prefer dc and the original transformer is too strong to drive the led.)
  • note:this is where you choose to use or not a power switch on the cord,or use the switch of your lamp.mine was dead with no feedback,so i removed it,broke it open,and glued back together the cover just to fill the hole of the lamp.
  • note2: the old transformer will be not connected but it will stay inside the lamp base,mostly as a weight to keep the lamp stable.
  • final step put the led bulb and enjoy!

Step 3: Converting Defective or Damaged Integrated Led Lamp.

this conversion can be done on defective or damaged integrated led lamps.

most integrated led lamp use main or 5v power.

using main power for a main lamp or 12v for a 5v lamp should fit the lamp wiring depending of the case.

but the conversion could need more involvement.

some function could be lost like tactile buttons or dimming.

the harder part being,bypassing the older circuits ,removing the old led and finding a way to fit the socket you want (g4,g8,g9 ,e14...)

note:if you feel adventurous you can use a 12v car socket and led light bulb.



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    6 Discussions


    1 year ago

    Do you have link for suitable g4 led bulbs ...looking for something about


    2 replies

    Reply 1 year ago

    you could use multiple g4 led (bigger fixture use 2 to 3 bulbs)

    or change all the cabling for some g9 gu10 or e14 light bulb as a minimum


    Reply 1 year ago

    no g4 halogen was max 40 halogen watts so it is around 300 to 400lumens so no in led you ll find 3w as a max...


    1 year ago

    I made the same project a few months ago. I have the same lamp and made this by removing the top part of the lamp and putting / hiding a diy AC-DC converter behind the plastic cover. Still a nice project!

    1 reply

    Reply 1 year ago

    Yeah I wanted to keep the project simple and solder less. With easily available components.

    Uncle Kudzu

    1 year ago

    Very useful information. I have a 12V halogen desk lamp with a bad power supply and now I know how to reclaim it with an LED. Thanks for sharing!