The circuit for turning off the sound signals is shown in Fig. 246. The signals are turned on without using an auxiliary relay in the mounting block and in place of the relay, jumper 3 is placed between contacts "85" and "87".
If the signal volume decreases and wheezing appears, adjust the signal by turning the screw on its body in one direction or another until a loud and clear sound is obtained. If the adjustment does not eliminate the wheezing or the signal works intermittently, then disassemble the signal and clean the interrupter contacts. When assembling the signal, install the previous gasket between the membrane and the signal body so as not to disturb the gap between the core and the anchor. This gap for the C-304 and C-305 signals is (0.4±0.05) mm.
If the signal does not turn on, check the reliability of the wire connections, the condition of the switch contacts in the mounting block. If necessary, clean the contacts.