Proper resistance for Q7 collector

[Neal Campbell and Sarah Ferrell]

I am progressing through debugging the bad resistance reading between
ground and the collector of Q7 on the RF board. I have it up to 900
ohms now. The manual says '>500' is a passing resistance. What is
'normal'? Is 900 ohms a sign that all is well?

73 de Neal

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[Don Wilhelm-3]

Neal,

The exact reading depends on your particular DMM.  The only real way to tell
is to use your DMM on another K2 and compare (or find someone else using the
same DMM).
With my K2, I read about 600 ohms when I first apply the test leads and
climbs to about 1000 ohms after a time - then reversing the probes, the
reading starts out at 600 ohms again and climbs to about 3K ohms after a
time.

If you remove the control board, you should see a more steady reading - in
my case about 1k with the probes in one direction and about 3K in the other.
With the control board installed, the readings vary as above largely due to
C28 charging through R16.

Actually, your 900 ohm reading may be just fine, but be aware that it will
be meter dependent.

73,
Don W3FPR

> -----Original Message-----
>
> I am progressing through debugging the bad resistance reading between
> ground and the collector of Q7 on the RF board. I have it up to 900
> ohms now. The manual says '>500' is a passing resistance. What is
> 'normal'? Is 900 ohms a sign that all is well?
>
> 73 de Neal
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
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> Elecraft web page: http://www.elecraft.com
>

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[Neal Campbell and Sarah Ferrell]

Well, just in case anyone searching the archives for hints on a similar
situation, I had a solder bridge on the top of the RF board between the
case of Q5 and the lead from R44 that fed from the bottom, just
impossible to see without magnification, etc.  Probably no one will
make the same mistake but just in case, thats what caused this one.

Neal
On Feb 2, 2005, at 10:30 AM, W3FPR - Don Wilhelm wrote:

> Neal,
>
> The exact reading depends on your particular DMM.  The only real way
> to tell
> is to use your DMM on another K2 and compare (or find someone else
> using the
> same DMM).
> With my K2, I read about 600 ohms when I first apply the test leads and
> climbs to about 1000 ohms after a time - then reversing the probes, the
> reading starts out at 600 ohms again and climbs to about 3K ohms after
> a
> time.
>
> If you remove the control board, you should see a more steady reading
> - in
> my case about 1k with the probes in one direction and about 3K in the
> other.
> With the control board installed, the readings vary as above largely
> due to
> C28 charging through R16.
>
> Actually, your 900 ohm reading may be just fine, but be aware that it
> will
> be meter dependent.
>
> 73,
> Don W3FPR
>
>> -----Original Message-----
>>
>> I am progressing through debugging the bad resistance reading between
>> ground and the collector of Q7 on the RF board. I have it up to 900
>> ohms now. The manual says '>500' is a passing resistance. What is
>> 'normal'? Is 900 ohms a sign that all is well?
>>
>> 73 de Neal
>>
>> _______________________________________________
>> Elecraft mailing list
>> Post to: [hidden email]
>> You must be a subscriber to post to the list.
>> Subscriber Info (Addr. Change, sub, unsub etc.):
>>  http://mailman.qth.net/mailman/listinfo/elecraft
>>
>> Help: http://mailman.qth.net/subscribers.htm
>> Elecraft web page: http://www.elecraft.com
>>
>
>

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