After reading through posts here and other sites...I learned that there is supposed to be a 24v bulb in my Ampeg PR-410HLF panel, acting as a fuse for the horn. I haven't been able to find anything indicating what that bulb should be. I opened the back panel and found that the previous owner had placed a screw in the socket and used electrical tape to hold it in place. Therefore, I don't have an old bulb to reference. Does anybody know what bulb I need? Your help would be much appreciated!