The Fermilab Photo-Injector Laboratory currently uses a Philips YK1240 to drive its superconducting capture cavity. Over the last year, the perveance of the installed klystron has been gradually decreasing, thus limiting the available output power. Two of the three YK1240 klystrons which had been kept in storage were evaluated for use in the capture cavity system. The third klystron was not in a condition to be tested since its electron gun assembly remains disconnected due to a previous maintenance analysis. Serial number (S/N) V108SK-7 exhibited the best performance and is now installed in the system. The performance measurements are presented here to aid in planning the system maintenance program.