At my company, we're looking at repairing our David Clarke headsets, used by the engineers at the nosewheel, etc. in house.
When I was at QF, I did some time in components repairing DC headsets and we had a nifty little tester box. It ran off a 9v battery, had an on/off switch and simply had the one 1/2" audio jack to plug the lead into. If you plugged in, pressed the PTT button on the belt station or the mic dome and, if you heard yourself through the earphones, the headset was good to go.
Does anyone know where I might find a schematic or circuit diagram of said tester? It'll make repairing headsets a heck of a lot easier than tramping out to the aircraft to make a test call and still not being sure that A: the message is being heard and B: I can hear anyone talking on the other end.
Any advice would be great, especially from all my fellow cone heads out there!
Cheers,
John