[Elecraft] K2: KPA100 fan issue + current question

[Jim KO5V]

Don,

Yes, I set the bias as described, and at that setting, R6 is rotated about 1/3 clockwise from fully CCW (I saw a reference to that reference in the archives). My guess is that my 35 year-old Beckman meter may be having trouble measuring small voltages, so I'll try another meter, and I'll report what I find. 

Thanks!

73, Jim KO5V


-----Original Message-----
>From: Don Wilhelm <donwilh at embarqmail.com>
>Sent: Nov 9, 2018 9:56 AM
>To: Jim KO5V <ko5v at earthlink.net>, Elecraft List <elecraft at mailman.qth.net>
>Subject: Re: [Elecraft] K2: KPA100 fan issue + current question
>
>Jim,
>
>I would expect that the current at 100 watts would be closer to 17 or 18 
>amps.
>Has the bias been set correctly for a 400mA rise in PA current with no 
>RF input?  That bias setting will alter the operating class of the 
>amplifier and it must be correct to be linear.
>
>73,
>Don W3FPR
>
>On 11/9/2018 11:46 AM, Jim KO5V wrote:
>> Well, after checking that all of the components in the fan circuit were correct, I decided to follow Don's usual advice about checking my soldering, so I re-flowed all of their joints. None looked bad, but now the fan works as it should, so...
>> 
>> I'm still curious about my 11A @ 100W measurement. I think I'll borrow a friend's DMM and see if I get the same voltage measurement across R1
>> (unless 11A is in the ballpark).