NOTE: I am nowhere near the first person to do this. I got my steps for this from http://users.adelphia.net/~kiltz/.
Anyway, modifying your beatmania controller's turntable will allow it to move more easily. The increased sensitivity will especially benefit pinky scratchers who find that they aren't moving the turntable enough due to it being too stiff, but this mod is for everyone who thinks that their turntable would be improved by it being looser.
Step 1: Gather Materials
You will need the following:
Phillips Head screwdriver (I used the one from a cheap multitool)
Something to cut on (not pictured. Be sure that whatever you use won't get punctured if you press down really hard (the newspaper I used unfortunately didn't work so well).)
Small container for the screws (also not pictured)
Step 2: Eject the Keys
Push in that black button on the back of the controller, and slide the keys out. Put them aside.
Step 3: Unscrew the Bottom
Use your Phillips Head screwdriver to unscrew all the screws from the bottom of your controller. You should put them in some sort of small container to keep them from getting lost. After unscrewing it, set your controller's bottom aside.
Step 4: Remove the Turntable
Turn the top part of the controller upside down so you're looking at the inside. Unscrew the screw in the middle of the turntable assembly, and set the top aside. Be sure to put the screw somewhere safe.
Step 5: Cut Out Circles From the Wax Paper
You're going to cut two circles from the wax paper the same size as the clear plastic circles inside the turntable.
First, tear out a large section of wax paper. Fold that in half, so that you will get two circles from one cut. Put that on top of whatever you're using to cut on (and if you use newspaper, please use a whole lot of it. I didn't and I messed up the tablecloth).
Next, place a circle onto the wax paper. Trace around it with the Xacto knife. Go slowly so that you do a neat job, and so that your Xacto knife doesn't slip. You might want to use some scotch tape and lightly tape the circle to the wax paper so that it doesn't move. I didn't though, and I held it in place just fine with my fingers.
Finally, remove your circles from the wax paper. Throw away the middle part, you won't need it.
Step 6: Tidy Up Your Circles
I had a lot of jagged areas of my wax paper circles, so I cut those away with my Xacto knife. I also had some areas that needed to be smoothened out a bit, so I cut away some material to make them smooth.
Step 7: Put the Circles Into the Turntable Assembly
First, place a wax paper circle onto the turntable. Then, put a plastic circle over it. Then, put a wax paper circle over that, and finally put the remaining plastic circle over the wax paper circle.
Step 8: Reassemble the Controller, and Enjoy!
First, screw the turntable assembly back into the top of the controller. Next, screw the bottom back on. Finally, put your keys back in.
Enjoy your slippery and very sensitive turntable! The only side effect from this mod is that the turntable makes a slight "swish" sound when it is moved, but it's not that noticeable.