A friend who knows way more about electronics told me that it was most likely the switch circuit that was burned out and that the LED's should be OK.
So with a broken SAD light to play with i decided i would have a go at getting it to work.
I opened the case of the light and found it was one large printed circuit board. I used a heavy weight pair of scissors and cut the control circuit of the board.
I checked the power supply and saw that the output was 12v at 800ma so I figured that it would be safe enough to cut the jack plug of the power supply strip the ends tin them and poke about until i got the LEDs to work. I did exactly that and with a quick study of the board and a few attempts i found enough points on the board to solder the wires in place so all the banks of LED's would light up. once Found the correct points I used some solder paste to help make soldering the wires in place easier.
With the SAD light now back to being HAPPY again i had the idea to use it on the clip on anglepoise lamp i have on the wood lathe. check this link I had never truly happy with the 12v system, just not enough light.
I just used a couple of wood screw to fix the plastic case to lamp stand. The power cable was then cable tied to the anglepoise frame and lucky enough there is enough power cord to reach a plug socket. there is no on off switch other than on the plug socket but then that's enough anyway.
The LED SAD light makes a great light for wood turning but i screw the head unit of the lamp stand to the wrong side of the lamp, i found that i could not get the light positioned to shine into pieces of work that i was hollowing out. this was a simple fix just unscrew the head unit and fix it to the other side. with the lamp in its new position i can position the lamp so i can get the best view on turning projects where I am hollowing out the piece.
Also I get the benefit of the SAD lamp on those dark winter days when I don't get enough sunlight. i normally work with rolled up sleeves so as i work at the lathe under the rays of the lamp I'm getting that Vitamin D that I don't get enough on the dark winter days, with the added bonus of not having the nasty UV rays in the spectrum. also because the lamp is angled down it is not as hash on the eyes as when you try and sit under one of these lights.
Thanks for looking I hope you like the idea.