London Underground Central Line Audible Alarm Unit - Design & Replacement of Combined Power Supply / Power-Amplifier Printed Circuit Board

Scope Description The proposed tender is intended to secure LUL 92TS Central Line Audible Alarm Unit (AAU) - Design & Replacement of Combined Power Supply (PSU)/ Power-Amplifier Printed Circuit Board (PCB) updates required on the 1992 Tube Stock (92TS) Central Line of the Preliminary Market Engagement document. Context: TfL is exploring market interest and capability for remediation of 92TS Audible Alarm Units (AAU) by replacing the combined Power Supply Unit (PSU)/Power Amplifier Printed Circuit Board (PCB) inside each AAU, carrying out required factory and site testing, and returning fully functional AAUs for service. The AAU comprises two internal boards -   Combined PSU/Power-Amplifier PCB  Voice synthesis PCB  Failures have occurred exclusively on the Power Supply Unit (PSU)/Power-Amplifier PCB, which is no longer supported by the Original Engineering Manufacturer (OEM). Given the AAU's safety-critical function, trains cannot operate without it, making obsolescence remediation essential.    TfL intends to proceed in phases:  Phase 1 - Development of 2 prototype combined PSU/Power-Amplifier PCB units (PCB design validation, Final Acceptance Testing (FAT) and Site Acceptance Testing (SAT))  Phase 2 - Production of 18 units of combined PSU/Power-Amplifier PCB subject to prototype approval.  Phase 3 - Potential Future Demand (option) - up to 180 additional combined PSU/Power-Amplifier PCB units  Objective: Identify suppliers with capability to design, replace, and test PSU/Power-Amplifier PCBs within existing AAU housings, while maintaining fit, form, and function equivalence. Understand supplier approaches to obsolescence management, aiming for 15-20 years of ongoing support. Assess capacity to deliver through a phased model: prototypes, batch production, and potential scaling. Evaluate supplier test and assurance capability, including: Final Acceptance Testing (FAT) Site Acceptance Testing (SAT) Compliance with RIA 12 and EN 50121-3-2 (EMC), and BS EN 61373 Cat 1, Class B (shock & vibration). Gain insight into market best practice for low-volume, safety-critical electronics.