RESOLVED: Simplex 4051 help

Hey guys. My simplex 4051 sounds terrible with unfiltered power, and doesn’t even work on filtered power from my panels. Just wondering if there’s something I can do to clean it to get it to work or of anybody has any ideas. Thanks!

Oh and the metal plate does move in when it’s running on filtered power. It just makes a quiet screech sort of. Not a horn sound. Other horns work great

What are you powering it with? Insuffient current can make them sound very weak like you described.

Silent knight SK-5208 and a Silent Knight SK-4

5208 has filtered power, SK4 does not

Did you try loosening the volume screw on the front of the horn? It’s a small red screw inside the grille on the metal plates.

The SK-5208 and SK-4 should have enough power for a 4051.

Yeah I did try messing around with the volume screw to no avail.

Okay, there’s four nuts on the back that control the electromagnet’s position. If you be very careful you can move those nuts to change the magnet’s position. Do it right and you’ll find the sweet spot where the horn is loud. If you watch my video where I converted a 4051 to a 4050 you can see me adjust the nuts on my horn.

It appears that was the trick! I moved the magnet back out a little and it sounds brand new. Thanks!

Your welcome.