K1 kit not showing resistance values at test points

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K1 kit not showing resistance values at test points

Andy kb1kyn
I am building the k1 kit and am at the rf board, part 1 test section. Of the eight points to be tested on the 20 pin connector only four are showing values. The meter on the other four is indicating "of" or overflow, which the meters manual indicates as infinity. The values in the instructions do say the readings should be ">100k" . The other test points are on two amplifiers and of those only two of the five are giving readings, the others showing "of". I have checked the part locations and have found no mix ups. Any body have any thoughts?
Thanks
Andy, kb1kyn
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Re: K1 kit not showing resistance values at test points

Don Wilhelm-4
Andy,

Your "of" indication is a valid measurement - therefore it is a "reading"
It is a higher resistance than the range your meter is set to - switch
to a higher range.
Once your range is above 100k, if it still indicates "of", you know that
the resistance is greater than 100k, therefore all is well.

For the other points, do the same, increase the meter scale until you
see a numeric indication on the meter, or if the range exceeds the
expected resistance, and you are looking for a value greater than that
listed, the test passes.

Often, you are asked to check the resistance of a point that has nothing
connected to it - that can and should have infinite resistance.  The
purpose of doing that test is to check for solder bridges or other
shorted conditions.

For measurements like this, ohmmeters vary in how they display large
resistances.

Please tell us which specific pins you are having trouble with.  Use the
designators given in the manual and we can communicate unambiguously
without guessing what you meant.

73,
Don W3FPR

On 2/16/2014 10:03 AM, Andy kb1kyn wrote:

> I am building the k1 kit and am at the rf board, part 1 test section. Of the
> eight points to be tested on the 20 pin connector only four are showing
> values. The meter on the other four is indicating "of" or overflow, which
> the meters manual indicates as infinity. The values in the instructions do
> say the readings should be ">100k" . The other test points are on two
> amplifiers and of those only two of the five are giving readings, the others
> showing "of". I have checked the part locations and have found no mix ups.
> Any body have any thoughts?
> Thanks
> Andy, kb1kyn
>

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Re: K1 kit not showing resistance values at test points

Andy kb1kyn
Thank you don for your points. First off the meter I am using has a maximum range of 40 M Ohms and I tested each point using the maximum range setting. The pins that indicated an "OF" reading were number 6, 7, 8, 14 and 16. All had a specified resistance of >100 k except for 16 which specified>1k. The amplifier U3 pin 5 specified >10k and amplifier u4 pin 6 specified >10k  and >1k at pin 7. I appreciate all the input.
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Re: K1 kit not showing resistance values at test points

Don Wilhelm-4
Andy,

On the ohmmeter range, for the most accurate reading, use the scale that
is just above the resistance value you are expecting.  In other words,
if you are expecting greater than 10k ohms, use the 20k scale.
or if you are expecting less than 1k, use the 2k range.

If you are using a meter with auto-ranging, pay attention to the range
indicated.  If there is any confusion, switch to manual ranges.

73,
Don W3FPR
On 2/16/2014 10:11 PM, Andy kb1kyn wrote:

> Thank you don for your points. First off the meter I am using has a maximum
> range of 40 M Ohms and I tested each point using the maximum range setting.
> The pins that indicated an "OF" reading were number 6, 7, 8, 14 and 16. All
> had a specified resistance of >100 k except for 16 which specified>1k. The
> amplifier U3 pin 5 specified >10k and amplifier u4 pin 6 specified >10k  and
>> 1k at pin 7. I appreciate all the input.
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/K1-kit-not-showing-resistance-values-at-test-points-tp7584318p7584335.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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