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Re: [IP] transmitter going bad??



I just received today a replacement transmitter.

I'd been having tons of the Lost Sensor thing going on, especially during
the initial startup period. And Sensor Error, Weak Signal, and Calibration
Error... Usually, it would settle down and mostly work after a while -- the
older the sensor, the more reliable it became.

The polite nutcase I spoke to at Minimed kept insisting the problem had to
be scar tissue. Scar tissue does NOT turn on and off. Polite, courteous,
professional, but technically nuts. Probably not his fault -- he was
probably trained that way.

So I watched it for a couple months. Was very, very sure the problem was
intermittent contact -- since disturbing the connection between the sensor
and the transmitter would immediately wake it up, the little green light
would start blinking -- sometimes even raising my shirt would be enough to
wake it up. I took my time; I didn't want to waste time on the phone without
solid-enough evidence to get action.

As I was about to call a second time, switching out the sensor I was giving
up on (which was out near the edge of my abdomen where the curvature is
greater, which I've determined was a factor... it hit me -- I should be able
to demonstrate the problem with a freshly-removed sensor, outside the body!
Unlike the nutcase tech support guy, I know the sensor doesn't dry out and
stop reacting on the scale of a second or two.

Sure enough -- applying a slight bending moment in the concave (i.e.
opposite curvature of the body) direction, would turn it on. Applying a
similar bending moment in the other direction, would turn it off again.

My theory is that after the sensor had been connected for a while, the
o-rings would gradually settle in and allow the transmitter to make a bit
better contact, which is why they'd work better after a while.

I suspect my particular transmitter was just out of mechanical tolerance for
a good contact. And there's a bit of bad engineering there -- the contacts
should probably go the other way, so taping it to your body gives better,
not worse, contact.

Anyway, my conclusion is that Lost Sensor can be an indication of Bad
Connection.

This time when I called Minimed, I got someone who grasped the idea that it
wasn't scar tissue that made it do this (perhaps not being connected to my
body helped, but she also seemed to understand about the off-and-on timing,
mechanical manipulation, etc. all being arguments against it).

I hadn't planned to send this on just yet, since I haven't tried out my new
transmitter to verify it addresses the issue, but I happened to pop in and
see this thread. I'll try to remember to pop back in again in a few weeks
and give an update.

I just don't have time to read this list anymore. Being so busy, it sure
does help to have CGMS -- except those days when it's wasted too much time
being flakey. I'm hoping the new transmitter is better about Weak Signal,
too -- we'll see!
.
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