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• Past modifications to transmitter improved reliability by replacing components with high failure rates, high repair costs or both
• Wholesale replacement of the transmitter is considered to be "cost prohibitive"
• Transmitter Refurbishment consists of 3 subprojects:
  • Transmitter Backplane modernization
  • Transmitter Pulse Modulator Upgrade
  • Transmitter Chassis Refurbishment

Transmitter Backplane Modernization

• Transmitter Backplane and Control & Monitoring CCAs are based on 1980's technology and have become difficult and expensive to repair.
• Project replaces "Wire-Wrapped"backplane design with modern multi-layered Printed Wiring Board (PWB) and combines the functions of 4 C&M CCAs onto a single multi-layered CCA
• Fleet Implementation will be through use of a Mod Note beginning in FY16. Downtime should be minimal (<2hrs).

Pulse Modulator Upgrade

• Eliminates "Top 3" failure items in Modulator:
  • RBDT Switch Assembly, Trigger Amplifier, Backswing Diode Stack
  • Trigger Amp will be retained in cabinet to maintain good airflow, but it will be inoperative
• Requires addition of new:
  • High speed Fiber Optic Switch Assembly
  • Optical Discharge CCA - Converts electrical trigger signals to fiber optic signals required by new switch
  • RBDT Stack Monitor CCA - Monitors the voltage across the RBDT stack

Modulator Switch

Transmitter Refurbishment

Pulse Modulator Upgrade

• Modulator Switch Prototype Testing
  • 1 prototype and 3 beta units delivered for test
  • Prototype operating on ROC test bed since July 2008
  • 3 Beta units operating reliably in field since January 2010
• Scope of SLEP Effort
  • SLEP will fund the production and deployment of the new modulators
  • Deployment method is a round robin - sites receive upgraded modulator drawer and return the legacy for upgrade and reissue

Transmitter Chasis Refurbishment

• Cable Replacement:
  • Cables become brittle over time, develop open circuits, broken pins on connectors, etc
  • In general, cables are either high voltage with lug terminals or signal cables
  • Documentation of wiring is incomplete
• Component Replacement:
  • One-For-One Replacement: fuse holders, cable connectors, power filters, main breakers, centrifugal blowers
• Refurbishment performed by commercial contractor(s) selected through competitive procurement process
• Estimated Transmitter downtime is 5 days.