It is hard to find the replacement bulbs today for old projectors and even when you find them they cost you a fortune and do not last very long.
As an upgrade or alternative LEDs are quite a good choice. Sadly the do not come with those old sockets and power specs of the projectors.
In my case a Eumig Mark 502D with a 8VAC 50W bulb of the type SL-17 with a CXR CXL socket.
But since we are in the 21st century we are lucky to have possibilities at hand to make it work. I am speaking of 3D printing and LED of course.
The following steps will tell you in a short way how to replace the bulp with a standard MR16 12V LED. which will most likely last longer the the other hardware in the projector.
Also this solution is extremely cheap and replacement bulbs can be found everywhere.
Step 1: 3D Print the LED Bulb Holder
The holder I designed works for the Eumig Mark 502D as shown in the picture. For other projectors you need to find others or let me know. I do offer a 3D modeling servic.
The 3D model here is licensed according to http://creativecommons.org/licenses/by-nc-sa/3.0/
Step 2: Electric
You need 2 parts you can find online. Some cables and a soldering station
1. 1 bridge rectifier that is rate at least for 12V
2. a GU5.3 socket
Make sure there is no possibility the conntacts can short circuit (use shrink tube)
Connect the bridge rectifier to the cables serving the power to the old bulb socket. Either solder some cable to it or disconnect the cables from the old socket. Normaly the bridge rectifier has some symbols like ~ showing the AC input connect the cables there.
Next connect the GU5.3 socket to the brige rectifier. The have to be connected to + and - on the bridge rectifier.
Step 3: Assemble Everthing
Take the printed bulb holder and put the bulb into it. It will be a very tight fit and you may have to smoothen the edges a little to let the bulb pop into the holder. Unce inside secure it by screwing 1 M4x12 screw in.
Next screw the holder onto the projector like in the picture using 2x M4x12 screws.
Connect the GU5.3 socket to the bulb.
Thats it. Try out if everything works by turning on the projector and test the new bulb.
Last thing to do close the projector and start your movie.