K2 problem with 4 MHZ calibration

[Mike Scott-7]

K2 Problem (serial No. 4159)

Hello dear builders...I have a problem.
At the 4 Mhz Oscillator calibration a problem occurred:

First the counter did not show 12090 +/- 30 KHz but: ~ 8.9 MHz

I checked the board and discovered that I had made a mistake with D16; then
I soldered D16 in the correct way and the measurement now is around 7,5 MHz
(with built-in frequency counter)

- verified all components and their polarity, all seems ok (yes - X1 is the
12,09 MHz oscillator)

I verified the frequency of the oscillator with the help of my FT-1000MP and
yes, around 7.562 KHZ you can hear the oscillation...

by the way: the VCO Test is OK

a friend who has successfully built a K2 thinks perhaps the 12.09 MHz
oscillator is faulty...

what do you think...so far the building was fun and successful...but now i
do not know what to do..

THANK YOU VERY MUCH for your help

Very 73 de Markus, DL9RCF

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[Don Wilhelm-4]

Markus,

For now you do not know if the problem is with the counter or with the PLL.

Is your friend close enough that you might be able to borrow his K2
control board (and his internal counter probe) for a quick test?

If so, then substitute the known working control board for yours and
measure the PLL frequency.  If it still indicates a frequency in the 7.5
MHz range, then you have a problem with the PLL circuit, but if it
indicates a correct range for the PLL, then you have a counter problem.

Do not make any menu settings with the substitute Control Board because
the settings will be written into your friends EEPROM - restrict the
testing to the counter indication.

In either case, check the soldering carefully.  Most failures are caused
by improper solder connections.

73,
Don W3FPR

Mike Scott wrote:

> K2 Problem (serial No. 4159)
>
> Hello dear builders...I have a problem.
> At the 4 Mhz Oscillator calibration a problem occurred:
>
> First the counter did not show 12090 +/- 30 KHz but: ~ 8.9 MHz
>
> I checked the board and discovered that I had made a mistake with D16; then
> I soldered D16 in the correct way and the measurement now is around 7,5 MHz
> (with built-in frequency counter)
>
> - verified all components and their polarity, all seems ok (yes - X1 is the
> 12,09 MHz oscillator)
>
> I verified the frequency of the oscillator with the help of my FT-1000MP and
> yes, around 7.562 KHZ you can hear the oscillation...
>
> by the way: the VCO Test is OK
>
> a friend who has successfully built a K2 thinks perhaps the 12.09 MHz
> oscillator is faulty...
>
> what do you think...so far the building was fun and successful...but now i
> do not know what to do..
>
> THANK YOU VERY MUCH for your help
>
> Very 73 de Markus, DL9RCF
>
>  

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