Incidentally, a blown fuse on 5V line at 1Y2 rack was found during the intallation of Sorensens.
The fuse (5A 125V) has been replaced and fixed.
When I plugged the fuse in, I heard some sound like relays were switched. Are there any relays in the LSC rack?
It was a 9th fuse from the top as seen in the picture.