Gimbal Issure - Not cycling properly on startup

[Victorian Aerial Vision]

Recently I managed to crash my drone into a bridge by coming up too early. (sound effect added)

After this the only issue with the drone was that the fan no longer worked but everything else seemed ok. I flew for a month or so without the fan which was no problem so long as I avoided having the drone turned on for any more than a couple of minutes without being in flight, the drone movement & the wash from the props would keep the drone cool. Finally I decided I had to fix the fan, hoping for something as simple as a dislodged plug or something like that. As it turned out the problem simply was that the fan had been knocked out of alignment & was easily fixed. The gimbal problem began after I reassembled the drone. I keep getting a gimbal motor overload error & you can hear the gimbal hitting the stops in vertical travel of the startup sequence. The gimbal moves freely but it doesn't travel to the stop in the upward direction. I don't know if this by design or there is something wrong mechanically. Being the gimbal was working correctly before I pulled the drone apart (I didn't remove the gimbal, I just unplugged it so I could remove the fan, I assumed I failed to plug something back in correctly. I have tried refitting all the plugs several times to no avail. Below is a video of the fault in action, you can hear the gimbal clicking when it hits the stops, it never used to do this. Has anyone seen this fault before & know the cause of it?

EDIT: I have tried a gimbal calibration, but it always fails. I presume for the same reason, the gimbal won't cycle properly.