I am getting no signal on the DJI go app from the camera. The drone fly's just fine but the camera does not connect. Is it cheaper to send it in to DJI for repair, or spend the $259 for a new gimbal and camera?  I purchased and received the phantom 3 about 3 weeks ago. First flight, sadly hit a tree and bent the gimbal roll arm just slightly. The phantom flew perfectly fine after. In fact, I flew it several times and everything worked great. But, because of the bent roll arm, I could not move the camera all the way facing straight down. I ordered a replacement roll arm. I took the gimbal apart, installed the new roll arm, put is back together, and the camera worked just fine. I was able to tilt it up, tilt it back down. Worked out great. The following night, I took it out to fly. It warmed up like normal, the dji go app started like normal, I could see the blades of grass through the app on my phone, I went to take off and th screen went grey, then displayed NO Signal. Could this be because I messed something up? Is this a known issue and was just dumb luck that it happened after my repair? Did I kill my chances of a warranty because I made a repair myself? Any suggestions on a fix? Again, would this be cheaper to buy a new gimbal or send to DJI? Would a new gimbal fix the problem?
Thoughts anyone?

First off, it's not a know issue. If you crash and replace components yourself and it works for a bit then stops working I wouldn't call that a known issue.
The issue is your camera is no longer transmitting a video signal back to the RC. Check the ribbon cables to make sure they were not damaged in your crash and they are fully seated in the slots.
If you cannot get video after that then you probably damaged the video transmission module and I would send it in to DJI for repair. You can call 818-235-0789 and they will send you a prepaid shipping label.

Thank you Ken. I'll try the ribbon cable and go from there.