Door handle operates day latch but not full locking system

[paltibine]

We have a composite door with a 3 point locking system and a wind latch to stop the door opening even when it's not locked.
This morning the door wouldn't open and my wife said it felt odd when she locked it last night. It didn't seem to be properly locked with the 3 point system and after a lot of fiddling with the handle and the key I managed to get it open which seemed like a win at the time! However, now the door handle only operates the wind latch when you press it down and pulling the handle up, which used to operate the 3 point system does nothing. The key won't turn in the eurolock because the 3 point system isn't locked.
So I took the handle plates off and underneath them are 3 holes with square drive, two standard size for the handle spindle and one much smaller square drive.
One of the large ones where the handle spindle goes through operates the latch but nothing else, the other large one only operates the 3 point mechanism and it seems to work fine. I tried to turn the small one with a flat blade screwdriver but it doesn't turn easily although the latch moves slightly when I try to turn it.

Is there any chance of getting this to work again without trying to take the whole thing off and getting a new gearbox if that's possible?

To satisfy my curiosity does anyone know what the small square drive is for?

Thanks in advance for your help folks!

 

[paltibine]

Does anyone have any ideas on this? Isn't it quite rare for a post to go months without any responses?

 

[Mottie]

If it’s anything like mine, it was a cam broken inside the lock. I managed to replace it.

Help! Door mechanism broken inside.

What can I do? Replace the whole thing? How do you know what to buy? Where do you get them from this time of afternoon?

www.diynot.com

 

[paltibine]

It's quite likely you're right. I haven't been able to get the mechanism out yet as the screws are so tight. They are definitely some sort of cross head drive but I can't really get either a Pozi or Phillips driver not to cam out. I guess it could be the Japanese one but I've only ever come across those on Japanese cars.

Luckily it's only a porch door and there's a good lock on the main house door but I'd still like to fix it if possible.

 

[Harry Bloomfield]

It's quite likely you're right. I haven't been able to get the mechanism out yet as the screws are so tight. They are definitely some sort of cross head drive but I can't really get either a Pozi or Phillips driver not to cam out. I guess it could be the Japanese one but I've only ever come across those on Japanese cars.

My door gearbox/lock, jammed up a few weeks ago, except our's refused to unlock/open. After eventually getting to open, it was the gearbox which had failed. If yours is anything like mine, the multi point locking strip needs to be undone, screwed to the door edge, with PZ screws - don't try to undo any, but those screws. The strip, complete with lock, should then slide out of the pocket in the door.

Gearboxes vary in types and measurements, you must get the correct type/size. Some only come with the multi-point attached.

 

[paltibine]

Thanks for all your input folks!
I'm feeling very pleased with myself as I managed to fix it at zero cost (but a lot of time).
I finally got the locking strip off having got my manual impact driver out and removed the gearbox. As soon as I removed it a bit of curved metal fell out which turned out to be part of the cam.
I spent ages on the interweb trying to find a replacement gearbox but nothing I found fitted the dimentions and the reference number on it turned up nothing.
So I took it apart and sure enough one of the cams was broken and another part of the cam fell out. After fiddling with it for a while I realised that there were two identical cams, one of which wasn't actually used in this application and unsurprisingly that was the pristine one. So I just swapped the two cams over, put it all togeher and refitted it into the door!
Works perfectly!

If anyone is interested the small square drive was for a "snib" to keep the latch in the open position.

 

[johndiy21]

Your composite door's locking issue likely stems from a faulty gearbox in the multi-point locking system. Try lubricating, aligning the door, or resetting the gearbox. If that fails, replace the gearbox or call a locksmith.

 

[crank39]

A chatgpt reply if ever I saw one.

If you read the update you'd see that the OP has fixed the issue so no need to replace the gearbox or call a locksmith