On the battery placement for the B unit ,a D cell battery seems tight fitting in the battery box,is this normal, horn works well, just asking because it looks like it sits at a angle before it makes contact.
Sorry I meant the non powered unit, not B.
Has the non-powered unit's frame been the receiver (in the past0 of a leaking D-cell battery? If so, the metal around the insertion port may be 'swollen" from the acid attack.
Another possibility is the battery bracket may be bent or mis-adjusted from its normal position wherein the battery would make vertical contact with the bracket post.
No the battery box is in very good condition, bracket is fine.