There are places making LED heads (white light and variable contrast) for some enlargers. They are not cheap. Some people have made homebrew LED heads that work, too.
Originally Posted by Hatchetman
I'm early on in the process of testing an off-the-shelf 60 watt equivalent LED which cost $10 at my local Lowes (a Utilitech Pro bulb). I had to choose carefully because many of these have very uneven light patterns or oddball designs or other quibbles which would make them unsuitable as a condenser light source on a timer, luckily my old timer has mechanical relays and will switch the small load of an LED bulb without trouble. The bulb I'm trying out illuminates very evenly across its surface just as the PH140 does and puts out maybe 3/4 of the level of light which is still plenty. But I need to bodge together a lamp holder which will position it at the right height as it's about an inch longer than the PH140 and a bit too wide to fit in the stock lampholder; the heatsink fins prevent it from screwing in properly, though it will fit down into the lamphouse without any problem. Even then, I'll have to see how it affects contrast.