ASCO K473670-003 Transfer Switch Board 300 Series Group 1

ASCO K473670-003 transfer switch control board is the 240-volt variant of the ASCO Series 300 Group 1 controller PC board used inside automatic transfer switches. The part is listed as 473670-003 (K473670-003) for 240 V operation, and ASCO documents it as a discontinued 300 Series Group 1 controller with a suggested replacement part number 955717-001. This board is designed as a drop-in replacement for the Group 1 controller PC board and, where specified, voltage sensing is configured via DIP switches on the circuit board. In aftermarket listings, the K473670-003/473670-003 controller is described with features such as solid-state voltage sensing, interchangeable heavy‑duty power transformers, a high‑efficiency switching power supply, and an RS-485 full‑duplex communications port with ASCObus II protocol, along with support for local and remote annunciators. It is intended for use with ASCO 300 Series Group 1 automatic transfer switches to manage transfers between two power sources, using the existing cover, tray, and mounting hardware.