Looks like Radio Shack still two analog models, One for $25 and one fro $30.

Larry A.

On Fri, Jul 4, 2014 at 8:02 AM, Larry Alofs <lalofs@gmail.com> wrote:

> Scott,
>   Do you have a link?  When I search at the HF site, all the meters are
> digital except one that mounts in the dash.
>
> Larry A.
>
>
>
> On Fri, Jul 4, 2014 at 3:50 AM, SDF ( aka ;jim lahey' - Scott ) <
> scottdaniel@turbovans.com> wrote:
>
>> if your goal is an inexpensive basic analogue volt meter..
>> they can be as low at $ 4.95 or even $ 3.95 at Harbor Freight ..and in
>> Oregon ..no sales tax either.
>> or...
>> like 15 bucks will go a long way toward getting one that's decent enough.
>>
>>
>> On 7/3/2014 1:56 PM, Rocket J Squirrel wrote:
>>
>>> David's suggestion to use an analog voltmeter is a good one. Analog
>>> meters catch glitches and dropouts that digital meters don't.
>>>
>>> The question is -- who has a good value in an analog multimeter these
>>> days? Simpsons were my go-tos in Ye Days of Olde when Knights Were Bold
>>> and I had a budget.
>>>
>>> --
>>> Jack "Rocket j Squirrel" Elliott
>>> 1984 Westfalia, auto trans,
>>> Bend, Ore.
>>>
>>> On 07/03/2014 04:12 PM, Harold Teer wrote:
>>>
>>>> David,
>>>>
>>>> Thanks for a great and detailed explanation on the AFM that even I
>>>> understand.  Between the information from you, Karl, and Neil, this
>>>> thread
>>>> will be a wonderful resource in the archives for understanding the AFM
>>>> better.
>>>>
>>>> Have a great weekend and 4th of July,
>>>>
>>>> Harold
>>>>
>>>> Harold Teer
>>>> 1991 Westy -- VANGAUX
>>>> Harrisonburg, VA
>>>>
>>>>
>>>>
>>>> On Thu, Jul 3, 2014 at 5:08 PM, David Beierl <dbeierl@attglobal.net>
>>>> wrote:
>>>>
>>>>  At 09:10 AM 7/3/2014, Harold Teer wrote:
>>>>>
>>>>>  Thanks, this makes sense in theory. Â Can you walk me through how
>>>>>> to do
>>>>>> this without the AFM connected if I don't have any fancy equipment.
>>>>>> Â Do
>>>>>> have analog and digital meters so have that part covered.
>>>>>>
>>>>>>
>>>>> To do it with the AFM in the van, follow the procedure in tencentlife's
>>>>> video.  Pull the boot off the connector, stick your meter probes in
>>>>> as he
>>>>> shows, turn on the ignition and follow his procedure of very slowly
>>>>> pushing
>>>>> the AFM vane open with a stick of some sort.  You have to be slow
>>>>> enough
>>>>> that the meter has time to respond to any dropouts.  Notice he's
>>>>> using a
>>>>> fairly small meter with a fairly quick-responding needle.  If you
>>>>> have a
>>>>> larger one that responds very slowly (like a couple of Radio Shack
>>>>> meters I
>>>>> have) you have to move the vane slow enough that you can see the needle
>>>>> dip.  Any dip at all means a problem at that point on the track, you
>>>>> don't
>>>>> have to wait for it to fall to zero; you should see the voltage only
>>>>> rising
>>>>> as you push the vane open.
>>>>>
>>>>> To do it using dry cells or a power supply (and having been reminded by
>>>>> Neil's photo of the resistor plate itself, I expect a nine-volt square
>>>>> battery would be fine and maybe easier to hook up to), hook up the
>>>>> battery
>>>>> to the same pins the ECU would use.  I don't have access to a
>>>>> Bentley right
>>>>> now but according to the video the AFM pins for the waterboxers are:
>>>>>
>>>>> 1 - Temp I hot
>>>>> 2 - AFM wiper
>>>>> 3 - AFM + supply
>>>>> 4 - System ground for both AFM and Temp I
>>>>>
>>>>> So you'd hook B+ to pin 3 and B- to pin 4.  You'd hook meter + to pin 2
>>>>> and meter - to pin 4.
>>>>>
>>>>> Don't use your digital meter, it will only cause you grief. It probably
>>>>> only takes 2-3 readings per second, and the reading is averaged over
>>>>> the
>>>>> sampling time which is less than half of the half- or third-second
>>>>> cycle
>>>>> time.  If your meter has a quick-responding bar graph display you might
>>>>> manage; but the analog meter responds in real time and is always
>>>>> reading
>>>>> the line.  Even if the needle response is slow it will be easier to
>>>>> deal
>>>>> with than the digital (may or may not be easier than the bar graph
>>>>> display.
>>>>>
>>>>> If for some reason you do use the digital, set it on a fixed range,
>>>>> as you
>>>>> don't want it switching ranges while you're testing.
>>>>>
>>>>> Set your meter range as low as practical that's at least half the input
>>>>> voltage.  As tcl says that will cover the part of the AFM track that
>>>>> gets
>>>>> the wear.
>>>>>
>>>>> FYI, if you look at Neil's photo of an uninistalled resistor plate:
>>>>> https://lh6.googleusercontent.com/-c5axVMck2Ks/T-tDy8qL_MI/
>>>>> AAAAAAAAF2o/Cly2OSeHmUk/s912/AFM%2520Board%2520Wear.jpg
>>>>>
>>>>> At the bottom there's the Bourns name and Bosch symbol, indicating a
>>>>> proprietary part made for Bosch.  8712 means it was made in week 12 of
>>>>> 1987.  The two crosses and two triangles I imagine are registration
>>>>> test
>>>>> marks for the several layers of stuff that get printed onto the ceramic
>>>>> substrate.  The spot on the left-hand triangle may be an inspector's
>>>>> mark.
>>>>>   The long number is Bourns' part number for the plate, the 1
>>>>> probably means
>>>>> revision 1 of the device, and the reversed C looks like a test
>>>>> resistor to
>>>>> validate the resistor printing process for quality control
>>>>>
>>>>> Above that is the wiper track. The right side is the ground side and
>>>>> the
>>>>> left side is hot, corresponding to the rotation of the vane in the AFM.
>>>>>
>>>>> Now look at the very top.  The two bright dots are where the spring
>>>>> contacts have burnished the silver paint that forms the conductors.
>>>>>   Theleft one is + and the right one -.  Following them, you'll see
>>>>> that
>>>>> each connects to a green patch with lines on it.  Those are
>>>>> resistors, and
>>>>> the lines are where the trimming laser burned away parts of the
>>>>> resistor to
>>>>> increase its resistance to the correct value.
>>>>>
>>>>>  From the other end of the resistor conductors go to the two ends of
>>>>> the
>>>>> wiper track.  If they were the only connections you'd be able to do
>>>>> this
>>>>> test with an analog ohmmeter instead of a voltmeter.  But as you can
>>>>> see
>>>>> there is also a resistor that stretches the entire length of the track,
>>>>> with nine connections into the track and laser trims between each
>>>>> pair of
>>>>> connections.  That's what's driving your ohmmeter nuts.  It's a voltage
>>>>> divider that's feeding an offset voltage into the track at those nine
>>>>> points to adjust the wiper response.  When Bourns builds the plate the
>>>>> laser trimmer has point contacts that leave the tiny bright mark on the
>>>>> little side tabs coming away from the various resistors, and it
>>>>> trims the
>>>>> resistors in a particular sequence until all the values are
>>>>> correct.  It
>>>>> looks as though it does a roughing pass and then a finishing pass to
>>>>> take
>>>>> care of interaction between the voltage divider and the two main input
>>>>> resistors.  Then they ship it to Bosch who glue it onto the metal
>>>>> mounting
>>>>> plate.
>>>>>
>>>>> While I'm on the subject, in tcl's video the long copper arm is carries
>>>>> the contact from the AFM connector to the wiper.  It has a carbon
>>>>> button in
>>>>> the round end ant there's a flat spring with a bump on it that comes up
>>>>> from the vane/wiper assembly and presses on it.  However apparently
>>>>> there
>>>>> were difficulties with this, because by at least late '83 Bosch had
>>>>> added a
>>>>> braided copper flex cable to bypass this button and make a solid
>>>>> connection.
>>>>>
>>>>> Yours,
>>>>> David
>>>>>
>>>>>
>>>
>