As entitled; the total power of each light source of the oplev was getting reduced to almost zero. The light sources for MCe and MCi were replaced to new ones.

• MCe: [old] #203256 -> [new] #228155 around 18:15-20 JST
• MCi: [old] # 203253 -> [new] #228160 around 19:10 JST

For each case, as the collimator and the light source was connected with a fiber connector, so just replacing the side of the light source was just what I did. The power supply including the AC adapters were remained to be used. These old ones will be sent back to the company for repairing.

Thanks to the fiber connections, the beam positions on QPD did not move so much between the before and the after. For MCi, we switched to lower gain on the QPD circuit board, as the readout from the circuit would be saturated when the new light source was connected. And also for MCi, we slightly tweaked the QPD stage so that the light beam can illuminate the center of the QPD.

Let's see the time decay...