[AudioI] Zero card stopped working -- will order new hardware to troubleshoot

[Tom Garwin]

I had finally declared victory over extraneous noise in my remote
microphone prototype set-up and was prettying up the power and signal
wiring allowing a powered stereo microphone and opamp preamp to be
separated from the pi/AI zeros -(-wifi or clock cycles may have been
causing interference in the powered mic)   -- but then  the AudioInjector
zero card stopped processing sound.

Its failure was accompanied by very strange things so it may be the Pi Zero
that failed (or both) rather than the AudioInjector.  I may have not taken
adequate precautions against electrostatic shock to the boards.

Specifically a set of commands to record the sound on one pi and send it
via SSH and aplay it on another stopped working.   I could SSH (by wifi)
into the first pi and could ping the second pi and even ssh from the first
pi into the second pi so this was strange.  They are both on the same
network with a unifi edgerouter with no intervening firewall so that wasn't
the problem.

After several reboots ssh was working normally again but the sound on the
pi zero was not..   dmesg shows a set of errors that seem to  relate to
voltages not being present --using default regulator (or something like
that) and there is no final  message saying the mapping is ok.  I cannot
capture a sound file that has anything but silence in it even though I know
the AI Zero board is getting appropriate input.   I also cannot get it to
play anything to its output.  Nevertheless the aplay -l and arecord -l show
entries for the audioinjector and it is the only soundcard in the system.
Alsa settings are what they were before.    Of course I did not look at the
dmesg output when things were working so I don't know if this is really
different.

So either I did something to fry the pi or the board or the both, or in
trying to fix the problem I updated the OS to a configuration that no
longer works.,

I suppose I could start over with a fresh os install and see if that works
but at this point I am guessing it is a hardware issue and the pi zero and
the AI zero are inexpensive enough relative to my time (and my inadequae
software skills)  that it's best to just try a fresh AI zero with a
different raspberry pi before trying a new software install.

Will keep this list posted on the results -- Only posting this now on the
off chance someone else has had the same symptoms.

-- 
Tom Garwin
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