Date:         Thu, 3 Jul 2014 10:47:43 -0700
Reply-To:     Neil N <musomuso@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Neil N <musomuso@GMAIL.COM>
Subject:      Re: AFM test readings
Comments: To: Harold Teer <teer.vanagon@gmail.com>
Comments: cc: David Beierl <dbeierl@attglobal.net>, Karl Wolz <wolzphoto@q.com>
In-Reply-To:  <CAGwfHKQRAfKQTCcsbfAgBFGL9f9f0-wsMY8+DLoHVUz-YedyfQ@mail.gmail.com>
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You're welcome Harold.

Of note, I found this comment from Tencent interesting:

"On this particular AFM, moving the wiper hub at top did not show any
problems, while moving the air vane did, so even slight pressure on
the wiper hub can alter the pressure of the wiper on the track enough
to mask a problem. "

As a side note, if one decides to move the wiper board so wiper can
contact fresh resistive track, beware. The screws holding it down are
tight and can be a minor hassle should one strip at the head. BTDT.

My coffee hasn't kicked in yet, so grey matter is still slow (er), and
Tencent likely explained, but my guess is that since the AFM is
supposed to operate off vehicle supplied ~ 5 Volts, supplying that to
AFM while measuring voltage output of AFM, gives a more accurate
indicator of resistive strip condition, wiper contact, etc. than using
the VOM supplied voltage (lower?) to measure resistance. i.e. putting
the resistive strip under ~ 5 Volt load creates a "real life" test.

David or someone of that ilk (read: someone who knows way more than
I), will likely clarify the "volts and ohms" behind this.    ;)

Neil.

On 7/3/14, Harold Teer <teer.vanagon@gmail.com> wrote:
> Neil,
>
> Thanks for alerting me to the video.  Here is the link to the thread and
> video.  "
> http://www.thesamba.com/vw/forum/viewtopic.php?t=369815&postdays=0&postorder=asc&highlight=tencentlife+afm+video&start=0
> "
>
> I had previously tested without power to the AFMs and noticed a linear
> change in one and a jerky change in the other.  From the video, it appears
> I need power for the proper test and will try that later today.
>



--
Neil n

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