Diablo 1340 terminal?

Hi all- Tonight I got a Diablo 1340 hardcopy terminal. It looks like a table with a Diablo 1550 typewriter on top of it, but the typewriter is part of the table. Inside the large black box under the table are power supplies, cardcages, fans, etc. It works, except for one thing: whether in local or remote, whenever the 1550 gets a carriage return, it rams the home hard stop and the ALARM and PRINTER CHECK lights go on. I press ALARM to reset it and it works fine until the next carriage return. I tried adjusting the home stop in and out (it's actually a stiff spring-loaded stop) with no luck. When the terminal is first powered on and it seeks home (slowly) it does fine, without hitting the stop. Any ideas? (BTW this thing is just jam-packed with 7400 series logic and a couple of chips I can't identify. It was built in 1974 and installed in May 1975- I even got the maintenance record with this thing. It's serial no. 769.) Richard Schauer rws(a)ais.net