AKG DHT700 noise

[electronicsuk]

Hi all. I have a fault with an AKG DHT 700 handheld transmitter where it seems to be putting out a lot of noise and very little signal. This is a fully digital transmitter so not a problem with the RF link. I've ruled out the receiver as it works fine with another transmitter tuned to the same frequency.

 

RF level from the faulty mic is perfect. Battery level, mute status etc all working as they should so I strongly suspect something on either the capsule or the input to the transmitter. It's picking up much more noise than signal and the only sound I've managed to pick up is by removing the mesh and either shouting into or tapping on the capsule, which sends the receiver into AF clip.

 

My initial thought was to replace the capsule but it' s soldered and glued in place, so I'm loathed to transplant one from a good mic and risk breaking both unless I can be a little more sure. The noise has me puzzled as the gain on the faulty mic is set at 0db, same as one of the working mics, and yet I'm getting all this noise. Could that really be caused by a faulty capsule?

 

What do people think about the idea of removing the glue from the capsule solder connections and shorting out the signal wires? If there's a break inside the capsule and it's acting as an antenna, I guess this should make the noise go away.

[electronicsuk]

Never mind - I got curious while waiting for a reply and decided to take the thing to bits. Signal wire between the capsule and the transmitter PCB was broken (looked fine, but no continuity). Stripped it back by 10mm or so, re-soldered and all is good.

[paulears]

That's a useful report of a fault for future use - glad you took the time to report back,