[en] This article mentions two reports. The first one is the recovery of klystron power supplies (modulators) for the KEK electron-positron injector linac after taking carbon soot. At night on April 3 of this year, there was a serious fire at the Nextef facility which is near the klystron gallery. Carbon soot covered the power supplies and so on. The soot is liable to cause discharge of the power supplies. It was decided to clean all the components as quickly as possible. The restart of power supplies achieved on April 22 (19 days after), the beam injection in superKEKB ring on April 25 (22 days after). The second one is the consideration of fire measure of the power supplies for the future. The cause of the fire was identified to be an ignition of pulse-forming-network capacitor in a Nextef modulator. As soon as possible, the installation of the surveillance cameras in the klystron gallery should be done, and the installation test of the fire detection should be begun. (author)