Billy was briefly able to morph into the Blue Ranger when he was trying to stop Jason and Zack from fighting, but it was only after Billy was later revived that the five teenagers were finally able to turn into Rangers, as they had set aside their differences and were willing to lay down their lives to keep Earth safe.
In the original Mighy Morphin’ Power Rangers TV series, the Rangers had no trouble morphing into their Ranger forms when battling Rita Replsa’s forces for the first time.
Their movie counterparts, on the other hand, failed to morph numerous times, and spent nearly two weeks training so that they could unlock the Morphing Grid.