A customer in High Wycombe got in touch because an internal door would no longer open even though they still had the key and the locking mechanism appeared to operate.
I first slipped the latch back so the door could be opened and then tested the handle properly.
The fault became obvious straight away: the latch was not retracting far enough to clear the keep.
Once I removed the mechanism from the door, the failed internal component was literally dangling inside the gearbox.
There was no useful adjustment that was going to save it, so I replaced the failed gearbox with the correct genuine part from van stock.
After reassembly, I tested the handle, latch and locking operation several times and the door was opening and closing normally again.
