[Elecraft] [K2] Hi Current...still

[b.denley at comcast.net]

Don: 

You hit it right on the head.  Hooking up my W2 (only calibrated as it is programmed by Elecraft), then p ressing TUNE (very) momentarily pegs the met er on the 20 W scale!  So the K2 is putting out plenty of RF but cannot control the power out.  Where do I look next? 



Thanks again 

Brian KB1VBF 



From: "Don Wilhelm" <don at w3fpr.com> 
To: "b denley" <b.denley at comcast.net> 
Sent: Sunday, February 19, 2012 8:39:08 AM 
Subject: Re: [Elecraft] [K2] Hi Current...still 

Brian, 

I did not realize that it was the same K2 - so in that case, the toroids 
have not likely changed. 
Make the check on power control that I mentioned in response to your 
most recent reflector post. 

73, 
Don W3FPR 

On 2/19/2012 1:15 AM, b.denley at comcast.net wrote: 
> Don: 
> After sending the unit to you to align last year, I haven't touched T3.  The K2 was working fine until around the time I tried to install the KNB2.  I never could get that to work so I just put the jumper in. 
> 
> It's very late here.  I will check the PA voltages and current tomorrow and report back. 
> 
> Brian KB1VBF 
> 
> - Original Message ----- 
> From: Don Wilhelm&lt;w3fpr at embarqmail.com&gt; 
> To: b denley&lt;b.denley at comcast.net&gt; 
> Cc: Wayne Burdick&lt;n6kr at elecraft.com&gt;, don at elecraft.com Wilhelm&lt;don at elecraft.com&gt;, Gary Surrency&lt;support at elecraft.com&gt; 
> Sent: Sun, 19 Feb 2012 05:33:19 -0000 (UTC) 
> Subject: Re: [Elecraft] [K2] Hi Current...still 
> Brian, 
> Is this condition on one band, or does it exist on all bands? 
> The winding of T4 will affect all bands, 
> A Low Pass Filter problem will affect one or two bands. 
> Transmit into a 50 ohm dummy load - then: 
> Quickly measure the voltage at the base of Q7 or Q8 during a TUNE. It 
> should be between 0.60 and 0.64 volts. 
> Count the turns on T4 carefully, the green winding should have 2 turns 
> and the white winding should have 3 turns. The "link" wires should go 
> from the front of the transformer directly to the back (they do not wrap 
> through both holes).. 
> 73, 
> Don W3FPR 
> On 2/18/2012 10:15 PM, Wayne Burdick wrote: 
>> Did you check the winding on the PA transformer? If the impedance were 
>> much too low, the current could be too high. Could also be excessive 
>> bias current. What's the current drain in transmit mode, key up (i.e. 
>> tapping XMIT but not the key)? 
>> 
>> Wayne 
>> N6KR 
>> 
>> On Feb 18, 2012, at 7:09 PM, b.denley at comcast.net wrote: 
>> 
>>> 
>>> After getting the HiCur message, I replaced the two PA transistors, 
>>> the associated hardware, Q11 and Q13, and R50. Unfortunately I stll 
>>> get the same message: HiCur when I press TUNE with power any higher 
>>> than about 1.5 watts inot a 50 ohm dummy load. Any have any ideas 
>>> about what else might cause this problem? 
>>> 
>>> 
>>> 
>>> Brian KB1VBF 
>>> 
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