Abstract
- We tried to install a dedicated power supply unit for AA chassis in EYV1 rack because it worked well on ITMX reported as klog#20715.- CH1 of ADC1 which was the most noisy one became slightly quiet. But it didn't worked well such as the case on ITMX.
- ETMY situation seems to be something different from ITMX.
- Finally, we uninstalled the dedicated power supply unit and reverted all situations.
Details
As I did on ITMX reported as klog#20715, we tried to install a dedicated power supply unit for AA chassis.Because of the mount space, the power supply unit was installed in the EYV2 rack and was connected to AAs in the EYV1 rack with 10m cables.
As shown in Fig.1, CH1 of ADC which was the most loud channel got slightly quiet (Cyan -> Blue). But some channels e.g. CH0 of ADC0 got louder than the original situation (Magenta -> Red).
In the case on ITMX, all channels became quiet (~1e-2ct/rHz level).
So it seems to be different between ETMY and ITMX situations...
We also found that all screws for mounting AA chassis connected to the dedicated power supply unit must be loosened to see the effect of the GND separation for AA chassis.
If some screws remain, GND of the dedicated power supply unit and the regular power supply unit are connected.
(And also, GND of AC seems to be connected to one of DC18V unfortunately...)
Finally, we reverted the power supply situation as the original one because there is no effect with tightened screws and it's difficult to leave such a situation.
