Technical asst request for K2, serial #5669

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Technical asst request for K2, serial #5669

Hank Kryger

>
> Hi
> I am constructing a K2, serial #5669 and having a problem.        
> Input voltage 13.2 VDC
>
> Alignment test Part II    Page 60 manual
>
> 4 Mhz Osc Cal  worked fine.  freq was 12098.81
>
> PLL Ref Osc Range Test
>
> Also OK  Ref high freq  12098.78   ref low freq 12084.95   range 13.83
>
> VCO Test          Here I have problems.
>
> If I  use the  frequency counter probe connected to P6 and TP3 before
> using CAL FCTR  as described in step 6, right column page 60, I get a
> zero reading although the reading from to to time switches between 0
> and .08.  If I  remove the probe from TP3 and reconnect to TP 3 get a
> reading of around 28 Mhz which rapidly changes down to  00000.06.   If
> I was reading voltage I would tempted to suspect a discharging
> capacitor which I was  measuring.
>
> I did the following:
>
> Checked solder joints and proper location, value of, capacitors 30,  
> 71,  72,  73,  and 74.
>                                                                        
>                          D 21, 22, 23, 24, 25, and 26
>                                                                        
>                           L30  (reheated the connection of L30)
>                                                                        
>                           Installation of T5  (toroid was constructed
> by Mychael  Morovich )  spacing of wire appears to be correct
> Checked the wires for T5.   Zero Ohm between point 3 and 4  also zero
> ohm points 1 and 2.
> Measured resistance between 2 and 4 as well as 1 and 3.  Both readings
> give 334.9 ohm, T5 mounted on circuit board as described in manual.
>
> VCO alignment
>
> I went ahead and checked the VCO alignment.  When reading the voltage
> between ground and left sided of R30 I get a voltage reading of 8 VDC.
>  When I turn the slug of L30, nothing happens the voltage does not
> change.
>
Does anyone have any idea as to what I can do the elevate the problem?

>   Your help is very much appreciated.
>
> Have a nice day, 73's Hank WA9QJH
>

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