Last friday I observed that the coil driver (#4) used to control the input mirror was not working properly. It also made the crete produce an alarm sound when connected. We have replaced it with another coild driver (#1). In order to do it, we had to restore the connector number 4 that was missing in that coil driver.
We dispose of 6 coil drivers, originally used in TAMA, which are numbered from 1 to 6. (#2 is actually not numbered)
Here a recap on the coil drivers used for filter cavity and input telescoope mirrors. (See also attached pictures)