[Elecraft] K2 kit building problem

[Gordon LaPoint]

Don,
       I have about 220mv P-P on the base of Q6.  I'm off to check all 
the components in the base ckt of Q6, with just DC on the collector.  
This is in Tune with the Power out set to 2W.

Thanks,
Gordon - N1MGO

On 3/4/2018 3:10 PM, Don Wilhelm wrote:
> Gordon,
>
> It is doubtful (but possible) that Q6 is bad.  Did it overheat when 
> you powered up? - if it did, you would most likely have seen a wisp of 
> smoke.
>
> How large is the signal at the base of Q6 when you have 800mV P-P on 
> the collector of Q5?
>
> The base voltage on Q6 is higher than normal, it should be around 1.1 
> volts.  I would suggest you check all components in the base circuit 
> of Q6 first.
>
> 73,
> Don W3FPR
>
> On 3/4/2018 2:26 PM, Gordon LaPoint wrote:
>> I'm building a K2 kit and I have a problem.  I'm starting the 
>> Alignment and Test, Part III on page 77-78.   I have no rf out.  I 
>> have followed the rf through the tx chain and have a good signal at 
>> (RF board) Q5 collector (800mv P-P) using a 400Mhz scope.  I have a 
>> signal on Q6 base, but nothing on the collector.  The DC voltage (in 
>> TX) at Q6 is 12.0 Collector, 1.8VDC base and 0 on emitter.  I don't 
>> see anything wrong DC wise, is it likley that Q6 is bad?  What else 
>> should I look for?  With the radio off the R at Q6 emitter to ground 
>> is 1.8ohms, that looks normal, so I don't have any current flow in 
>> Q6, it looks like.