There actually are two versions, one version has the RF board mounted to the back of the remote and there is a small wire harness that plugs into the main (big) circuit board.

The second version (the one that you have) has the RF board soldered to the main board and sometimes when they get dropped hard, the solder lets go and the board rattles around inside.

The spring you refer to is actually the antenna for the RF transmitter, it is not a spring to hold the board in place.

If you look at the RF board, you can see the connector that used to be soldered to the solder pads on the main board. You can also see that those were surface mounted, they did not go through the main board. On the other side of the RF board you can see that the same connector is soldered THROUGH the RF board.

Here is the ONLY fix for you. Desolder the connector from the RF board and remove it, then solder the connector to the solder pads on the main board. Once the connector is soldered to the main board, set the RF board on the connector so the pins go through the RF board as they did before you removed the connector. Now solder those pins through the RF board.

As you can see, there is no way to solder the connector to the main board because you couldn't get a soldering iron between the RF and main boards. We have fixed quite a few of these, always after they have been dropped hard.

Good luck.