This job followed directly from Locksmith Stanwell 269. The patio door had a broken lock component, but the bigger problem was that the multipoint mechanism itself was not releasing and the door would not open.
I tried a number of non-destructive ways to get the door open without much joy, so I eventually had to work directly with the failed mechanism. Once the door was open and I could inspect everything properly, it was clear that the multipoint system was obsolete. Rather than immediately condemn the whole mechanism, I opened it up to see whether it could be repaired and save the customer the time and cost of finding a replacement solution.
At first glance, a small spring looked like the obvious fault. I replaced it, put the mechanism back together and tested it, but the problem had only changed rather than disappeared — it was now failing intermittently.
I stripped it again, cleaned it, lubricated it and tested it, but the fault was still there. On the third strip-down I removed the internal parts one by one and finally found the little bugger: a bolt was catching intermittently on the faceplate and blocking the whole mechanism. I straightened it, reassembled and tested again, then made a small adjustment to the edge so it could slide cleanly without catching.
That finally did it. The obsolete mechanism was working properly again and another difficult-to-replace multipoint lock was saved rather than discarded.
