GreenArc, SeldomFixit,
I seem to remember reading that if the nosewheel was not down 30 seconds after the mains, the stab trim would "hang" at the touchdown setting and only maint. could reset it to zero...
Don't remember where I read it though
You could try over on
www.airbusdriver.net or search the threads for A320...
Regards,
Shuttlebus