I recently got a new trane 3.5 ton heat pump.

The unit has two zones (upstairs and down). The downstairs zone gets very little airflow. I removed the damper motor for that zone and noted that the damper was not fully opening after being shut by the motor (its a power close, spring open damper)...with the damper motor removed and the damper fully open, airflow is good downstairs...So I am guessing the springs are worn on the damper...The dampers are a old 1990 california economizer...

The other zone damper doesnt fully spring open either (although we are getting adequate airflow)

Questions are, should the damper springs fully open the dampers...is it common that the springs wear out on these dampers... or am I missing something...is my best bet just to buy two new dampers?