Luxo Lamp LED Conversion

Convert a vintage Luxo florescent lamp to LED.  

This is the operating lamp head showing the LEDs installed.  The 10w LEDs are run at 300ma, and are very bright.  I chose daylight white 20mm x 20mm LED COBs available inexpensively from AliExpress.

View inside of the Luxo lamp head showing the hexadecagon shaped 0.062" aluminum heat sink/mount I made for COB modules.  This shape was chosen as it was easy for me to shape from a 8.5" square. The center 5 1/2" hole was cut using a bi-metal hole saw.

Each COB module is coated with a thin layer of heat sink compound before bolting it down.

This is a view of the hexadecagon mounting plate/heat sink.  I used PCB design software (Diptrace) to create the shape and place the LED COB module outlines.  I printed the shape and taped it to the aluminum and transferred all mounting holes to the aluminum using a center punch for each hole plus the outside rim shape points.  I "connected the dots" on the outside rim with a sharpie to create the hexadecagon shape on the aluminum and then cut off the excess using a metal shear.

Here is a view of the 1" threaded (#6-32) spacers used to hold the LED heatsink to the head.  It was necessary to keep the original inner plastic liner as it holds the 5" lens.  The 1" spacers just clear the plastic liner.  

I drilled the LED mounting holes and tapped them for M3 cap screws.  4mm would have been the ideal length, but I used the 8mm ones I had.  Using tapped mounting screws allows an LED COB to be replaced without dismantling the whole thing.

This is the modified power box - I removed the original Luxo florescent ballast transformer and replaced it with an LED power supply.  The LEDs I used have a 10v drop, so 8 of them = 80v.  The LED power supply is capable of 87v @ 300ma. -- it is important to use a "constant current" style of power supply for LEDs.

The power supply I used is the "Uxcell LED Driver 18-25W Constant Current 300mA High Power AC 85-265V Output 54-87V DC" unit available from Amazon.  I took the power supply board out of its plastic case and mounted the board inside the Luxo power box as shown.

300ma. does not drive the LEDs to full brightness, but still bright enough considering there are 8 LED modules.  The lower current keeps the temperature of the aluminum heatsink to under 80C.