[Elecraft] PLL Reference Oscillator Range and VCO Test

[Don Wilhelm]

Dick,

All that sounds good, and may not be the source of your problem.

You mentioned that you had a frequency counter.
Do the CAL FCTR test with BAND+/- using your external frequency counter 
and see if you obtain the expected frequencies.
If so, take a very good look at your internal counter probe, especially 
the insertion of the crimp pins into the housing.   If those crimp pins 
are not inserted correctly (with the crimp pin locking tabs locked in 
the rectangular holes of the housing), the signal from the test point 
may not be adequate getting to the control board.  Also the braid on the 
coax must be on the pin closest to the left side panel when the probe is 
attached to the Control Board.

I have not seen it lately (in the past 2 or 3 years) but a while back we 
had trouble with the frequency response of Q9 and Q10 on the Control 
board.  If your external counter test is good and the probe is in good 
shape, you could try replacing Q9 and Q10 with 2N2222 transistors - they 
will work fine up through all the frequencies that internal counter needs.

73,
Don W3FPR

On 4/8/2013 2:23 PM, Dickie M0AUW wrote:
> Hi Don,
> Many thanks for your quick reply.
>
> U5 pin 7 good 4.8v at + 0 at -
> U6 pin 1 good 7.68v at + 0 at -
> D16 and 17 checked, same voltage change as U6 pin1
> Q19 I'm getting a reading of 257 ohms
> C84 and 85 are checked and correct
>
> While I had the time I removed the thermistor board , all looked OK.
> I will double check RFC14 and if necessary rewind and re-tin; I will also go
> over all the soldering again, 9 times out of 10 its a bridge or a soldering
> issue but I have to say I can't locate anything yet.
> Will let you know how I get on
>
> 73s - Dick M0AUW
>
>
>
>
> --
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