Scuba Posted June 21, 2016 Share Posted June 21, 2016 Hi all, At the school I work at we have a 4 channel I/O pacha bay which goes to 3 other bays in the auditorium. A few months ago during a school concert, the signal coming from some microphones wasn't being registered by the sound desk. After sending signal in the four four channels. It's come to the conclusion that nothing is travelling to or from any of the channel. Is there a way to test the channels to accurately find out the problem. I just can't believe it's the same with all of them. Any help would be greatly appreciatedThanksScuba Link to comment Share on other sites More sharing options...
themadhippy Posted June 21, 2016 Share Posted June 21, 2016 easiest way is with a tone generator and sniffer,plug the genarator into the patch bay and wave the sniffer around the wires were you think the other end should be,the more evil way is to use a megger on one end and an apprentice grabbing each wire,when they jump youve found the other end Link to comment Share on other sites More sharing options...
indyld Posted June 21, 2016 Share Posted June 21, 2016 Be aware that installed cable runs, while they can fail, are pretty low down the order of testing. Particularly if the fault seems to occur across all ways. Much higher up is finger trouble, obvious connection errors and patch confusion and faulty kit used to test with. Not much happens to an installed cable in its life. Link to comment Share on other sites More sharing options...
Whiskers Posted June 21, 2016 Share Posted June 21, 2016 What sort of patch bay If yours looks like two rows of jacks like http://www.canford.co.uk/CANFORD-B-GAUGE-HIGH-DENSITY-JACKFIELDS-Broadcast-style then go to https://en.wikipedia.org/wiki/Patch_panel and read normalisation If you are not familiar with double innering you can get very very confused Note also that if jack plugs with full size tips are ever used the sockets on the field may be damaged, best to avoid. And if you know all this I will shut up RP Link to comment Share on other sites More sharing options...
Dave m Posted June 21, 2016 Share Posted June 21, 2016 What are the connectors? Is it xlr at the stage end and 1/4 jack at the other?http://www.gear4music.com/Recording-and-Computers/Behringer-CT100-Cable-Tester/27R?origin=product-ads&utm_campaign=PLA+Shop+-+Behringer&utm_medium=vertical_search&network=google&adgroup=1+-+Product+Level+-+Behringer&merchant_id=1279443&product_id=2871d1&product_country=GB&product_partition_id=111960165199&gclid=CMTmqt3Juc0CFUwq0wod3sMNgg#full-desI use one of the above, but in your case you'd either need a very long cable to help create a loop, or use a known good path and another lead to enable you to test the cables.First of all, just connect something to the floor like a CD player/mic and try each path for signalA lead tester is still a handy tool. Some others are more useful, depends on your needs Link to comment Share on other sites More sharing options...
Stuart91 Posted June 21, 2016 Share Posted June 21, 2016 A Rat Sniffer might be a handy weapon to have. Link to comment Share on other sites More sharing options...
DrV Posted June 21, 2016 Share Posted June 21, 2016 If you want to go lo-tech then an XLR of the appropriate gender with a couple of different value resistors between 1&2 and 1&3 and judicious use of an ohm meter can tell you a lot. You can readily distinguish between opens, shorts, correct connections, incorrect connections and usually shorts to ground and it's cheap, provided you already have the meter of course. Link to comment Share on other sites More sharing options...
kerry davies Posted June 22, 2016 Share Posted June 22, 2016 I would suggest you read again what Rob IndyLD writes and diagnose which part of the chain is at fault before going into detailed cable checks. I am more than aware that this is a school and that some helpful student might have done something under pressure. That's why I would get whoever experienced the problem to begin with to take me through the steps they had done. It might well be something utterly simple because in all my years I never knew an entire multi go down unless someone chopped it very obviously. Had the builders in? Link to comment Share on other sites More sharing options...
Scuba Posted June 27, 2016 Author Share Posted June 27, 2016 I've since bought the Rat Sound Sniffer (an excellent little gadget). Tested a couple of cables first, the lights all came on. Plugged it into the panel and nothing come on. Hmm Link to comment Share on other sites More sharing options...
Shez Posted June 27, 2016 Share Posted June 27, 2016 I assume by "patch bay" you mean a simple connection panel? The term patch bay generally refers to something rather different. Do you know the route that the cable follows? Are you able to access all of it? If only part of it is accessible, a tone generator and sniffer, as Hippy mentions, will likely be your best bet. Connect to one end and follow the cable until the signal stops. Do that from both ends to narrow it down. Builders / contractors can be a pain for damaging wires. Been there... Link to comment Share on other sites More sharing options...
Scuba Posted June 27, 2016 Author Share Posted June 27, 2016 I don't know if I able to access all of it. The boss is just about adamant of me not doing anything without an electrician, apart from tidying and ordering classroom supplies, despite my background. Anyway, I'll see what I can do with that. Thanks Shez I assume by "patch bay" you mean a simple connection panel? The term patch bay generally refers to something rather different. Do you know the route that the cable follows? Are you able to access all of it? If only part of it is accessible, a tone generator and sniffer, as Hippy mentions, will likely be your best bet. Connect to one end and follow the cable until the signal stops. Do that from both ends to narrow it down. Builders / contractors can be a pain for damaging wires. Been there... Link to comment Share on other sites More sharing options...
Brian Posted June 27, 2016 Share Posted June 27, 2016 I've since bought the Rat Sound Sniffer (an excellent little gadget). Tested a couple of cables first, the lights all came on. Plugged it into the panel and nothing come on. Hmm Have you taken the front panel off to see if anything is actually connected? It wouldn't be the first wallbox I've come across without any cabling going to it. Link to comment Share on other sites More sharing options...
Dave m Posted June 27, 2016 Share Posted June 27, 2016 Is he aware that an "electrician" is unlikely to know what he is even looking at?Hopefully there is no mains anywhere near the audio boxes Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.