I’m also having a problem with a Gamewell version of the FS450d. I took it apart to see how electromagnetic horns work. I put it back together and it screeches a lot and can barely get it loud like before. Sounds like a dying Simplex 4903-9217. I keep adjusting the screws and make very little progress. There’s these metal u shape objects that sit around the coil that brings the arm up from the diaphragm and when it hits the metal object above the arm it vibrates the horn. Can anyone with experience help me out on this?
I’ve made significant progress with the horn. The horn setup is very sensitive and everything must be place properly. I have replaced the screws with similar ones and the horn is loud again. The new screws aloud me to fiddle with the horn components more easily. The arm has to hit the the diaphragm as much as it can. This meant fiddling with the magnetic plates around the coil so the arm could raise higher. Then there are two contact points above the arm that have to hit just right in order to buzz the arm. If the contact points are touching or not touching it doesn’t buzz. It has to be placed like a nano meter which creates a tiny blue spark that buzzes the arm. So the horn is loud but the scratchiness goes on and off depending on how you move the alarm around. Might be because my screws are not tight but a similar fit, or it’s another problem I don’t know about. I’ll keep fiddling with it but it was a good learning experience as I am starting to study and reverse engineer old and newer fire alarm devices.
An important factor is making sure you have the correct torque on the screws. Once you’ve dissembled the horn, it is nearly impossible to match the factory torque on the screws without specialized tools.
If it really gets bad, I can give you the option of shipping the horn to me for adjustment. I have a torque tester/driver set that I’ve used in the repair of several similar mechanisms before (Faraday 5410 and 7410). As long as I have another factory original horn to go off of, I can match the proper torque on the screws. Ship it back, and it should be good as new.
Thanks for the offer. Unfortunately I dismantled both alarms so that won’t work. However I have restored it to an almost fixed state. The horn is loud but it is occasionally scratchy. However I just learned that this alarm uses Electromagnetic Induction to buzz the alarm, not a switching circuit as far as I know. I think my problem lies in there. Your right about the torque settings. It’s very sensitive, if you screw the magnet plates to tightly it won’t work. If you make it too lose it won’t work either. It’s going to be frustrating as I was unaware of how Vibratone horns work. The magnets have to move up and down enough to create enough movement of the arm and strike the diaphragm.
I have several Vibratones I would have used for comparison :lol: . Anyways, glad you’re getting somewhere with fixing it.
I also just got several Simplex 4050 and 4051’s in the mail yesterday. I’m a little confused because when I tested the 4051 on my desk it was quite loud. However when I put it on a 4 inch electrical box screwed into my wall, it’s loud, but not loud like before, maybe like 70db? It does vibrate the walls and floor which it’s supposed to do but it’s not piercing like before? Is this normal?
Yes, that probably means you over tightened the mounting screws. I have a 4051, and it sounds real bad if you over tighten the mounting screws. Another issue is your electrical box is not deep enough. If the back of the alarm is hitting the round back part on the box, then you need a deeper one. I suggest the 2 1/8 deep boxes rather than the standard 1 1/4 ones.
Well the other 4051 is quite loud on the wall. Is there a screw on the alarm that’s too tight? The volume screw is the longest it can come out. Maybe a screw on the back?
Could be. I’m not sure.