sundance-communications.com Forums Telephone Services Security, Alarms and Paging Weird sound system problem

I got a call Friday from my boss at UT that one of our meeting room sound systems stopped working. They tried all the inputs in the room and got no sound. My first thought was to replace the mixer/amp (Altec 1707C) which I did but to no avail. I checked all the wiring in the room and it was fine.
We have a monitor in the rack and it was getting sound. The building has a PA system and it is tied into each meeting room with a relay. We thought this was disconnected because the PA is not used anymore. My next thought was to disconnect the relay and just connect right from the speakers into the amp. Magically everything worked fine. Maybe the relay was stuck in the PA system position and would not let audio come out from the amp.
Any thoughts?

The relay pack needs power to operate without any power it will stay in the default setting which was most likely the PA. Nice job but you should have checked the amps output before you replaced it.

I did check the output with my voltmeter and it seemed kind of low. Interestingly there was no power supply on the relay. I had removed them from other systems before but I don't remember seeing the power supply. Guess it can't work without one like you said...the system did work fine before Friday and nobody was in the rack.