IC3600FPSU Relay Circuit Board is available Online at The Phoenix Controls at best Price. Trusted Turbine Spares Supplier. Buy Now IC3600FPSU. Worried about going out of date You can choose from a wide selection of GE Speedtronic Mark II, Mark IV, Mark V, and Mark VI products at our online store. Guaranteed best value and service! Serving our consumers is our main focus. Simply click in and place your orders right away.