That's the correct part, and the new versions should be metal. The older plastic version was weak and vulnerable to breaking meaning the mini-XLR no longer locks as you've discovered. The socket is fixed to a small board inside and to replace it you need to do the following:
- Place the transmitter LCD-down on a flat surface.
- Remove the 4 Torx screws from the back of the transmitter (clip can stay on).
- Hold the battery door carefully as you separate the 2 halves of the transmitter (the pin and/or spring may try and escape otherwise).
- Put rear casing half and battery door (with pin and spring) somewhere safe - also the small metal spacer near the mini-XLR socket which will now be loose.
- Remove the 2 screws securing the battery holder and wiggle it loose (can stay attached via the power wires).
- The small board for the antenna can now be freed (again, can stay attached via ribbon cable). Another metal spacer is underneath it - keep this safe.
- Remove main board securing screw. Board can now be freed.
- Remove mini-XLR securing nut and wiggle socket assembly to remove from casing (from the inside).
- Insert new socket assembly and affix securing nut.
- Check squidgy buttons above LCD are still in place, then refit main board (slight pressure is required as socket contacts are spring-loaded) and replace securing screw.
- Refit metal spacer and transmitter board.
- Refit battery holder (has plastic lip to secure transmitter board.
- Refit other metal spacer.
- Check you didn't pull the power/mute board out by mistake as the plastic power button overlay tends to fall off if you do.
- If all looks as it should, hold the battery door in place in the bottom half, refit the top half and screw it on.
It's pretty easy, just requires the right tools, plenty of light, preferably a tray to stop small components going AWoL and a gentle touch.
