[Elecraft] K2 VCO Test pg 57: Problem -reading 0000 kHz

Sun Jul 14 11:20:01 2002

Earl:

This probably on't help Chris' problem, Earl, but regarding your apparent 
'high drive' levels on 18 & 28 MHz, have you performed the K2 VFO ALC mod? 
This sounds, to me, like a classic example of the problem it fixes!

Though I cannot seem to find this article published on the Elecraft web 
site (yet... Eric?), I can supply a copy of it. It's titled:

            K2 Modifications for use with the KPA100
   June 12, 2002 Rev. A (applicable to all K2 Rev. A RF boards)

The mods also include a couple other items as well.

73,

Tom Hammond   N0SS

At 05:49 PM 7/13/02, [email protected] wrote:
>I took some measurements in my K2, Chris.
>
>At the source of the VCO source-follower transistor (Q18) I get RF
>voltage readings of about 0.4 volts on all bands except 18 MHz and 28 MHz
>where I get about 1.1 volts RF.
>
>At the gate of Q18 I get about 0.7 volts RF on all bands except 18 and 28
>MHz where I get about 1.9 volts RF.
>
>I have no idea why the signal level is so much greater on 18 and 28 MHz.
>If this is normal, you might try those bands for checking the output at
>TP1, because maybe the signal is so weak on your K2 (on 80m) that the
>K2's freq counter won't trigger.
>
>The frequency measured (using the K2's internal freq counter) at the same
>points is the VFO dial readout frequency plus about 4915 kHz for the
>lower bands and minus about 4915 kHz for 21 MHz and above.  These same
>frequencies appear at TP1.
>
>Pin 13 of U4 is 4.18 VDC on all bands with no apparent RF riding on it.
>
>I was mistaken about U4 pin 6.  It stays at 5.0 VDC on my K2 regardless
>of whether the display is on a menu item or not.  I haven't checked but
>maybe its function is for CAL PLL where it goes low.
>
>I'm assuming that your optical encoder (VFO knob) is working because you
>obviously are tuning to 4000.10 kHz in the 80-meter band to measure the
>output at TP1 per the procedure on page 57 (VCO Test).
>
>73, de Earl, K6SE
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