Those circuit boards will probably be only available through the official service channels. Those parts are available in europe but pretty expensive. Also packaging cost would be high I guess...
Can't you hard-wire it ? The circuit board is pretty straight forward and it would only take you a few hard wires, I know it's a dirty solution, but if parts are not available you need to be creative

Check our Download Section, there's a
product Manual for the 1200LTD, but the used circuitboard would fit yours (if it's not one of those ancient one >20 years old).
When you platter has trouble in keeping a steady pace it could be several things among which are: bad connection/soldering of the fader, bad connection between the ciruitboard and cable, bad connection at the other end of the cable, broken drive IC and there could be 1 or 2 more things wrong. Measuring is the only way out when you want to di it yourself...