[Raleigh]

My 40-150 had all sorts of spurious signals out of place when I connected it to the 20 ft. wire I use for an antenna at my workbench. I tried to figure out why, but gave up and put the chassis back in the cabinet, connected the original loop antennas, and all those problems went away.

Is the strong signal from a local radio station? Or some other electrical noise? Hard to see how you could get a strong signal with all antenna leads disconnected, but....

Try connecting the loop to the chassis while you align, even outside of the cabinet, and see if it will behave itself. On the 40-150 there were a lot of connections to the loop on the back cover and, IIRC, to another loop inside the cabinet. I used short test leads with alligator clips to connect them all while I aligned it, and that worked out OK. I don't know if your 40-155 is the same, but it's probably similar.