MATERIALS:
-LM317 adjustable voltage regulator
-5k pot
-240 ohm resistor
-.1uf capacitor
-.01uf capacitor (.1uf will work too)
-small perf board (to build the circuit on)
TOOLS:
-de-soldering braid
-needle nose pliers
-medium size flat head screwdriver
1 open housing
2 remove main circuit board
3 remove black plastic tape deck cover
4 There is an opening in the motor housing where the power wires are soldered. Wedge a flat head screw driver in this space and turn it to pop the cover off. Don’t worry if you crack the circuit board, you’ll be removing it shortly.
Underneath the cover is a little circuit board. This is a motor speed regulator. This was installed to ensure that the motor maintains a consistent speed. You will be removing this and installing your own ADJUSTABLE speed regulator in the Barbie housing.
5 Use a de-soldering braid to COMPLETELY remove the solder from the two points shown. This will reveal two tabs sticking through the board. If you have removed all of the solder you should be able to wiggle the tabs around freely
6 Next you’ll be removing the circuit board. This is an important step and should be performed with care. The tabs sticking through are connected to the motor itself. You want to remove the circuit board without damaging these tabs.
The tabs are flat and were pushed through a rectangular hole in the board. Then the tops of the tabs were twisted to lock the board down. What you want to do is twist the tips of the tabs so they are flat again and will slide freely through the rectangular holes.
Use a pair of needle nose pliers to do this and bend them carefully so they don’t break off.
7 Solder two wires to the points shown in the picture. It’s a good idea to use colored wire so you know where to attach the wires later. Red is positive, black is ground. The black wire is connected to two points. One is the tab farthest in and the other is a small peg connected to the motor housing. Connecting the black wire to this point grounds the motor housing. If you don’t do this, the magnetic field generated by the motor will create a considerable amount of noise in the main audio mix.
8 Push the cover back on and put it all back together.
