Carl's post reminds me of a grocery store I worked at. Paging and music were there just very low. Nothing documented as far as how the legs were laid out. There were multiple legs. Isolated to the one bad leg. Then had to start following that leg. Eventually I lifted a ceiling tile by one of the speakers I wanted to use for a test area and a wire nut fell out AND the music came back upstream from my break and in the rest of the store. Turns out this was a "new" section and they spliced it in using wire nuts. One of the nuts fell off and, in addition to this, the store would hang banners so somehow the wire nut got knocked off and the bare wire side jammed into the ceiling grid by the tile.

Secured the cable up into the ceiling so it could not be disturbed and problem solved!

If you don't have the tools noted above remove all the legs from the output of the amp. Grab a speaker and connect to the amp output and make sure the amp is not the problem. Keep your speaker connected while doing the next step. After this, start putting the legs back one at a time. When the volume dies then you have a problem on that leg. If there is only 1 leg then you will need to start working downstream from the amp or down the leg you have determined has a problem. You can now put the speaker back or take it with you as you work in case you come across a speaker you suspect may be bad. Keep in mind that as speakers were added they might have broken off into different legs as they added on. Go to the first speaker and pull the wire going to the other speakers. You should notice the first speaker work right (assuming the speaker is good and there is not a cabling fault between the amp and the first speaker). You can either go to the next speaker and rinse/repeat or work several speakers down if you are sure of the speaker wiring layout. Assuming 1 wire daisy chains all the speakers and discovering they started another leg somewhere will drive you nuts so I would advise following the wiring. Time consuming but eventually you will find the problem and have a good understanding of this system for future calls.

If this is a regular customer of yours, spending some time documenting how the paging is laid out can save you considerable time and stress when it comes to service calls.

Michael Meyer