[Elecraft] K1 building problem - VFO not working

[Don Wilhelm]

Check your transistor numbers.  K1 Q1 is a 2N7000 FET and not a 2N4124.  
The ZVN4424 goes in the T-R switch at location Q4.

The VFO transistor (well OK an FET) is a J309 at Q8.

Possible solutions for a "no VFO" problem are diode D17 installed 
backwards, and also D3 and D4 varactors.  Check the Parts Placement 
diagrams at the back of the manual if you cannot discern the banded end 
on the board silkscreen.

Inspect all components shown in the schematic sheet 1 marked "VFO" for 
proper values and reflow the soldering on those components using a hot 
soldering iron (750 degF).
Examine your soldering with a critical eye - if your soldered leads look 
like balls, then the solder pad did not receive adequate heat. A good 
solder connection should look like a "mountain" with a nice concave 
fillet - anything convex is suspect.  Also it is said that the 
connection should not look "like a volcano" which indicates either an 
improperly stripped and tinned toroid lead or a normal lead that did not 
receive enough heat.

Always watch for the solder to flow out both onto the component lead, 
and also onto the solder pad.  I have repaired many Elecraft 
transceivers just by re-flowing the soldering.

73,
Don W3FPR

On 8/21/2012 5:28 PM, Gordon LaPoint wrote:
> I also have a K1 that I'm building, with the same error code - no LO.  I'm interested in
> any of the possible solutions!
>
> Thanks!
>
> Gordon - N1MGO
>
> On 20 Aug 2012 at 13:34, Stan AE7UT wrote:
>
>> For those of you following this thread with bated breath.
>>
>> I did check the resistors and the transistor in the VFO.
>> They were right.... well at least the transistor was the one supplied with
>> the kit.
>> Apparantly the Q1-2N4124 was switched with a ZVN4424 in the parts supplied.
>>
>> The right one is on the way from Elecraft so I think that will fix it.
>> We shall see.
>>
>> Stan AE7UT
>>
>>
>>
>>
>>
>> --
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>> 50.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
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