Canford BP111 Interesting Issue

[RobbGG]

Hi Guys,

 

Been handed a beltpack with an interesting issue today. Mic cuts out intermittently, so naturally, took the thing apart to check over and test more thoroughly. Found that I can cause the mic to cut in and out by tapping on the unit (both on the circuit board and on the bracket holding the XLR connectors) which sounds about right for the issue, the interesting bit is that while the mic has cut out, I can make it start working again by pressing the signal button on either this or another beltpack.

 

I've looked at the schematic but I'm not that much of an electronics guys so I was hoping that someone with a bit more experience than me could help work out where the issue is. I can do more testing if that'd be helpful, haven't got much in the way of gear (multimeter, headset+cans system to test with) but can do any measurements that might help.

 

Thanks,

 

// Robb

[Brian]

I've seen this before. IIRC it was a dry joint on one of the component legs. The reason pressing call fixes it is that calling puts some DC on the audio line which re-biases the line. I'd just go around and check each solder joint is good.