gnomatron Posted May 21, 2011 Share Posted May 21, 2011 I have a condenser mic that seems to have stopped working for no apparent reason - an sm86. It was working fine last time I used it a couple of weeks ago but now I can't get anything out of it at all. I'm unsure whether it's the mic itself or phantom power on the desk - can anyone suggest any simple way to check, WITHOUT using another condenser mic or another desk, as I don't have easy access to either at the moment...! I also tried the mic on a firewire audio interface but can't get phantom to turn on on the interface - or at any rate get the indicator led to turn on. This worries me, is it possible that the mic itself has some fault that's trashing phantom power on these bits of kit? Link to comment Share on other sites More sharing options...
paulears Posted May 21, 2011 Share Posted May 21, 2011 It could be drawing more power than the phantom power supply can deliver? Got a test meter? stick it between pins 1 and 2 and then 1 and 3 - you should have volts on both. If there is a a fault - more likely to be in the cable than the mic or mixer, if they were previously working? Link to comment Share on other sites More sharing options...
gnomatron Posted May 21, 2011 Author Share Posted May 21, 2011 I tried my multimeter and got nothing, but the probes were too small to fit in the XLRs so I did it on the end of the cable. hmm. I tried a few different cables with the mic to no avail. Link to comment Share on other sites More sharing options...
paulears Posted May 21, 2011 Share Posted May 21, 2011 The holes on the end of the cable are the same size? However, if you found no voltage on the XLR outputs, you would seem to have found the problem? Link to comment Share on other sites More sharing options...
gnomatron Posted May 21, 2011 Author Share Posted May 21, 2011 no, I just unscrewed the XLR and metered over the solder points. Looks like I have indeed found the problem! How annoying. Link to comment Share on other sites More sharing options...
Bobbsy Posted May 21, 2011 Share Posted May 21, 2011 Stick some short lengths of wire into the mixer XLR (be careful not to let them touch) and measure across those. Doing it your way, it could still be either the cable or the mixer. Paul is right that the cable is the likely problem but it's worth just going one more step to be sure. (Or, I guess you could do pin to pin tests on the cable itself. If that fails then you have a culprit.) Bob Link to comment Share on other sites More sharing options...
gnomatron Posted May 21, 2011 Author Share Posted May 21, 2011 Ok, I managed to jam the probes into a desk channel, still no voltage. Also the cable works fine with 57 on the end of it. Hmm. Link to comment Share on other sites More sharing options...
themadhippy Posted May 21, 2011 Share Posted May 21, 2011 what desk are you using? there aint a global phantom as well as individual channel phantom that's been switched off? Link to comment Share on other sites More sharing options...
gnomatron Posted May 21, 2011 Author Share Posted May 21, 2011 &h zed 22fx, global phantom only, which is definitely switched on. Link to comment Share on other sites More sharing options...
Mixermend Posted May 22, 2011 Share Posted May 22, 2011 This mixer has a recessed push switch for the global Phantom, with an associated LED.But this LED is powered from the +15 volt supply - so doesn't 'prove' that the +48 volt Phantom supply is indeed present.In fact your measurement on the XLR seems to prove that it is NOT actually present!So contact A&H Tech support - from whom you will get great help, or contact your nearest A&H Service Centre, who will be able to help - this might be me in the SW of the UK! Link to comment Share on other sites More sharing options...
ceecrb1 Posted May 22, 2011 Share Posted May 22, 2011 I'd agree... looks like its time to box it up and let someone have a look inside and see what they can find... Again, first port of call can be the place you bought it from or direct to A&H.. Dont forget to post here what the problem was once its solved... we like to know for future incase it happens to us ;) Link to comment Share on other sites More sharing options...
gnomatron Posted May 22, 2011 Author Share Posted May 22, 2011 It does seem like it's probably the phantom on the desk. when I said it was "definitely" switched on I should have been clearer - the switch is definitely in the on position with the led on... I know better than to assume that means it's working! :) Good to know that the led isn't on the same power supply though. I don't have a spare desk available and I can live with using a 58 instead - it's just for the odd preshow announcement - so there's no chance of getting it repaired any time soon, sadly. Thanks for all the help folks! Link to comment Share on other sites More sharing options...
Bazz339 Posted May 23, 2011 Share Posted May 23, 2011 Is there a separate fuse for the phantom power? Link to comment Share on other sites More sharing options...
gnomatron Posted May 23, 2011 Author Share Posted May 23, 2011 It's definitely NOT the mic I can now happily say, as I got the mic working with a firewire audio interface today. Re. fuse, not sure, if there is perhaps it's internal? Link to comment Share on other sites More sharing options...
Jivemaster Posted May 24, 2011 Share Posted May 24, 2011 As it's global phantom, is anything else holding the phantom down? For example; is there anything plugged in that has pin one linked to pin three -maybe a mono jack somewhere... If there was an unbalanced component then the phantom may even close down (correctly) to prevent something dying. Link to comment Share on other sites More sharing options...
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