Hello ,
The TDS2024 went out of production in 2006 and has been out of support since 2011. Our service group still offers best effort repair but if the power supply is the issue I show them as no longer available.
If you like you might consider reviewing the service manual to troubleshoot.
https://www.tek.com/en/oscilloscope/tds1002-manual/tds1000-tds2000-series-service-manual
This document provides information for technicians to maintain or service a product. Information is given to the module level, and may include product care and cleaning tips, troubleshooting information, adjustments, and how to replace parts.