I'm not sure if my doppler is broke. Now I'm having problems I can't remember the noise of the machine when I turn it on - but its quite fuzzy when I turn it on. I'm finding babies heartbeat but its taking me ages & its quite hard because above it there appears to be a lot of interference. Its not showed me a low battery indication but I bought a new one this morning & its still the same. Doppler problem? Other problem?