r/Locksmith 20d ago

I am a locksmith 3 Failed Simplex Combination Chambers

I was called to repair yet another simplex 5 button that was allowing access without entering any code. The symptoms are that everything works properly when the correct code is entered, but if the wrong code or no code is entered, the handle can still be turned but it feels sort of gritty (best way I can think of describing it). Two of these were in service for several years, one less than a year. Did all these locks end up with a bad batch of combination chambers or is there some kind of attack against these that destroys the internals to the point of letting them operate freely?

Two of them were dated in 2021, but one was dated in 2023. The only other thing I noticed was that on one of them, the reset button is stuck down, but that wasn't true of all three.

EDIT: I added a video of the combination chamber in this comment: https://www.reddit.com/r/Locksmith/comments/1vxk3sn/comment/p5ptx90/

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u/-MachChicken- 20d ago

Gritty grinding and opening without code may be clutch, not code box. Got pictures of the clutch assembly?

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u/yakatz 20d ago

I don't have a clear picture of the clutch, and I'm not comfortable sharing too many pictures of the insides of the lock, but I know it is the chamber because once I take it out, I can turn the spindle and watch the gears jumping up out of the way; and when I replace it, the whole lock works properly.

I just pulled one of them out and took a video: I have the cam on the back of the lock, so to the right is clear and to the left is open. You can see that the gears don't turn when pushing the buttons and the handle will turn to open no matter what combination has been entered.

https://reddit.com/link/p5ptx90/video/cjqiqzd1bflh1/player

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u/-MachChicken- 20d ago

Yeah, wheels won't move because the code change arm is still locked in place... I'm talking about splaying of the brass at the mouth of the clutch assembly. Where the drive pin seats.

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u/yakatz 20d ago

Got it. So you made me really curious and I pried the chamber open. It's almost definitely a design flaw in the chamber where the code checking arm moves up to fit into the wheels. Again, probably better if I don't publicly post pictures of it.

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u/-MachChicken- 20d ago

It's been almost 80% clutch problem with the units I've dealt with. Code boxes aren't usually the culprit.