K3 SN 3757 resistance checks fail ?

[Ramiro Aceves]

Hi K3 friends.

I am Ramiro, EA1ABZ. I have almost finished K3 assembly and I have
reached "resistance checks" in page 45 of the assembly manual. The
measured resistance in U 12 is 445 omhs, and the manual states that
this resistance should be greater than 500 ohms ("although in some K3
it may be only slightly greater than 500 ohms"). Mi measurement is
below 500 ohms. Do you think that I should search for a fault.?

U13 resistance is 420 ohms, greater than 150 ohms, as manual says.



Thank you very much.
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[Ramiro Aceves]

2009/12/26 Ramiro Aceves <[hidden email]>:

> Hi K3 friends.
>
> I am Ramiro, EA1ABZ. I have almost finished K3 assembly and I have
> reached "resistance checks" in page 45 of the assembly manual. The
> measured resistance in U 12 is 445 omhs, and the manual states that
> this resistance should be greater than 500 ohms ("although in some K3
> it may be only slightly greater than 500 ohms"). Mi measurement is
> below 500 ohms. Do you think that I should search for a fault.?
>
> U13 resistance is 420 ohms, greater than 150 ohms, as manual says.
>
>
>
> Thank you very much.
>

I have made resistance checks at U12 with another multimeter (cheaper
one, the first one was a FLUKE 175 ) and I get more than 2 kohms,
forward and reverse polarity.

I have made some investigation: The fluke uses 7 V to make resistance
measuremens, and the cheaper one uses 0.6 V, so that could explain the
diference. What do you think?, Do you think that I sould worry about
the resistance checks or continue doing the Initial Power On Check?



Thanks

 Ramiro.
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[Don Wilhelm-4]

Ramiro,

Yes, the higher voltage can cause solid state active devices to conduct
and give you false resistance readings.

73,
Don W3FPR

Ramiro Aceves wrote:

> 2009/12/26 Ramiro Aceves <[hidden email]>:
>  
>> Hi K3 friends.
>>
>> I am Ramiro, EA1ABZ. I have almost finished K3 assembly and I have
>> reached "resistance checks" in page 45 of the assembly manual. The
>> measured resistance in U 12 is 445 omhs, and the manual states that
>> this resistance should be greater than 500 ohms ("although in some K3
>> it may be only slightly greater than 500 ohms"). Mi measurement is
>> below 500 ohms. Do you think that I should search for a fault.?
>>
>> U13 resistance is 420 ohms, greater than 150 ohms, as manual says.
>>
>>
>>
>> Thank you very much.
>>
>>    
>
>
> I have made resistance checks at U12 with another multimeter (cheaper
> one, the first one was a FLUKE 175 ) and I get more than 2 kohms,
> forward and reverse polarity.
>
> I have made some investigation: The fluke uses 7 V to make resistance
> measuremens, and the cheaper one uses 0.6 V, so that could explain the
> diference. What do you think?, Do you think that I sould worry about
> the resistance checks or continue doing the Initial Power On Check?
>
>
>
> Thanks
>
>  Ramiro.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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> Please help support this email list: http://www.qsl.net/donate.html
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>  

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