[Elecraft] K2 AGC Threshold Adjustment

[DolfinDon at msn.com]

Hi

This voltage will depend on the tolerance of the 8 volt regulator. If the 8
volt supply is on the low side of the tolerance then you will not be able to
reach the 3.8 volts. However 3.75 should be close enough as this is just a
ballpark adjustment. The final adjustment will be made later by turning the
AGC on and off and adjusting for no change in the background noise.

Don Brown

KD5NDB





----- Original Message ----- 
From: "Jim Stoneback" <jstonebk at shentel.net>
To: <elecraft at mailman.qth.net>
Sent: Monday, October 08, 2007 1:53 PM
Subject: [Elecraft] K2 AGC Threshold Adjustment


> Hi,
>
> When I built my K2/100 the threshold adjustment didn't go right, I turn
> trimmer R1 full CCW to get 3.74v on pin5 of U2 (full CW pin 5 goes to 
> 2.6v).
> This adjustment is supposed to swing U2 pin 5 fom from 4 to 8 v.  I 
> checked
> diode polarity, resistor values, everything but never did find the 
> problem.
>
> Now I'm building another K2 and have encountered exactly the same result.
> Anybody got a clue?
>
> 73,
>
> Jim
> Jim Stoneback
> K4AXF
> Drake SW8
> K2.ssb.100 sn 6194
> K2 sn 6263 (underway)
>