We recently had a new Nortel phone system installed at work.( I think its called a BSM200)
We have overhead paging, the phone system is connected to an old stereo ( amplifier, tuner and tape deck).
Once the phone system was installed the paging worked fine, but there was a terrible hum coming from the speakers ( except when someone was paging, then it would go away for the duration of the page)
The phone installers said we need a grounded loop to correct this.
I had an electrician install the grounded loop.
The hum went away.
But now we have problems with the paging system working intermittantly.
I have checked all the volumn controls etc.
Yesterday the paging system stopped entirely. I went to our stereo, and, just playing around, turned on the tuner, tested the paging system and it worked, so I assumed the tuner had to be on for it to work and someone had turned it off. Hours later I get a call that the system is not working again, and the tuner was still on.
Obviously I'm no tech wiz. I have no idea what the problem might be.
Any advise?
I know I am about to begin the " it's the other guy's fault" game between the installer and the electrician.

You may want to consider a vendor meet with the installer and the electrician to find out where the fault lies.

There are so many possibilities with paging problems. Even though this will probably be simple to fix, tracing the problem and finding the trouble will take a while.

Are you wanting to play music overhead when there is no paging? I am no BCM novice even but with the MICS/CICS Norstars there was a relay that switched music off when paging and then back on.

It was essentially a normally open switch with the music playing. I used to make up a double pole, double throw relay with about ten dollars of Radio Shack parts. The Paging Out was one input, the music was one input, there was one output to the speakers and the MICS or CICS relay allowed or denied a 12 VDC power supply to the coil of the relay.

Music normally went out just passing through the closed relay contacts. When someone dialed an external page, the page contact closed, 12 VDC pulled down the Radio shack relay contacts and the page announcement went to the speakers.

You could also try some simple radio powered by a wall wart transformer that would not induce a hum into the circuit. Maybe you just have too fancy a music source.

I think his problem is hardware, not setup. I would take the lid off the amp, and clean it up with compressed air can (for computers). Another sign that it needs cleaning, is if you play with your volume buttons (Tuner, MIC 1-2, AUX) you will hear noise.

Thanks for your suggestions everyone. We discovered it was our old amp that was shot. Put in a new one and it worked fine.

Good to know you got it resolved. Thanks for the update.