[Elecraft] K2 Alignment and Test, Part II issues

[Don Schroder]

Don,

I’m now confused. I did measure the resistance at the source of Q19, which measured 280 ohms.

Will voltage pass through a crystal only when it oscillates? I got excited when I saw the voltage on
both sides of L31 was 7.5 volts, but the voltage on both sides of diode D18 was zero.

I very much appreciate your help. I apologize if I am asking dumb questions, I’m trying to teach
this 75 year old brain. I’ll rotate the VFO and see what happens. I have much to learn!

Thanks much!
Don, KE0PVQ

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

From: Don Wilhelm<mailto:donwilh at embarqmail.com>
Sent: Saturday, September 29, 2018 3:38 PM
To: Don Schroder<mailto:donanddeena at hotmail.com>; elecraft at mailman.qth.net<mailto:elecraft at mailman.qth.net>
Subject: Re: [Elecraft] K2 Alignment and Test, Part II issues

Don,

The voltage is likely coming through RP2 and making its way through
L31.  That is not the problem.
VFO through a 10 or 12 kHz range.  It should vary.

When the crystal oscillates, you should obtain a frequency at TP3.  That
is your next challenge.
As I said in the last email, measure the resistance at the source of
Q19. It should be near 270 ohms.

73,
Don W3FPR

On 9/29/2018 4:02 PM, Don Schroder wrote:
>
> Hi Don,
>
> I finally got some time to check your suggestions. D18 is oriented
> properly, and it looks like C84 & C85 are marked 121 (kind of hard to
> read since they are installed). So I thought I would check voltages
> for the PLL Reference Oscillator circuit. Didn’t take long to find 7.5
> volts going into X1 (the crystal) and 0 volts coming out! I resoldered
> the  pins to ensure no cold joints, and still 0 volts coming out. Do
> crystals go bad, or is it possible I burned it up by too much heat on
> the casing when grounding it? I think I will need a new one before I
> can check the BFO.
>
> Thanks!
>
> Don, KE0PVQ
>
>