Audio Systems: Motorola Vibrasonic, amplifier stage, amplifier output

Question
I own the above reverb unit - actual model is EV5R, but many are close to this as to what I am looking for.  The chrome two-button unit that turns it on and adjusts the reverb has about 8 feet of cable consisting of 4 color wires (black, white, yellow and red).  They connect into the spring unit via a plug.  Someone cut off the plug and just left the wires.  I am trying to determine which wires plug into the proper sockets on the spring unit.  I noticed that you had a unit and wondered if you might tell me which goes where - ie:  Red - top right, black, bottom left, etc.
Thank you so much for any help you can provide.

Best regards,

Answer
Such an old unit. Finding the owners manuals and wiring guides is not likely.

Best way is to trace out the circuitry.  Two wires would be for driving the spring which would come from an amplifier output. The other two would be the pickup from the far end of the spring and would feed into the input of an amplifier stage for blending back into the main audio.  From there you could figure it out.

Hope this helps.