Sony 1-637-878 SRX4-CPU PCB Cards Circuit Board Processor Sn

Sony 1-637-878 SRX4-CPU PCB Card is a compact printed-circuit-board module that houses the processor for SRX4-series systems. Identified by part number 1-637-878, this Sony CPU PCB card is described in listings as the SRX4-CPU PCB Card or processor board, with some references noting a variant such as 1-637-878-12. Market databases and repair catalogs indicate the part has been discontinued by Sony, making it a scarce spare primarily available through surplus or refurbished channels. This board functions as the central processing component within compatible Sony hardware installations reliant on the SRX4 CPU architecture.