noise from electret condenser mic - a symptom?

I have a couple of devices with electret condenser mics - a couple of Windows CE devices and a built-in mic on an iPhone hands free adapter. The mics work but are noisy. Recordings on CE device have a rumbling noise over them (not from wind). With the iPhone adapter and other CE device, a popping sound appears every second or so over any recordings. The CE devices are ~10 yrs old & didn't have these symptoms until a couple of years ago. The iPhone adapters are probably a bad design (mismatched mic capsule?), I got a different batch of these cheap on Amazon and they don't have this problem. Anyway, does anyone recognize these symptoms as something that can be fixed by replacing the mic capsule?