http://elecraft.85.s1.nabble.com/K2-BFO-Test-Problems-tp443892p443895.html
I thought I'd write describing what the issue was for the record. In
the end it was a bad connection on U10 of the Control Board. Pin 13
was not soldered correctly, so V BFO was incorrect. When tested on
hovered around 5.5 Vdc). I much appreciate the effort of Gary AB7MY
> Craig,
>
> The problem is most likely in one of the following areas:
> 1) The L33 inductor
> 2) The varactors
> 3) The crystals themselves.
>
> The very most likely problem is a poor solder connection, and the
> second
> most likely is misplaced components.
> The DC voltages look to be within reason, and it is probably not
> the fault
> of U11.
>
> We can get to precise measuremnts tomorrow, it is getting late here
> today.
>
> 73,
> Don W3FPR
>
>> -----Original Message-----
>>
>> Hello again,
>>
>> I've continued my troubleshooting efforts but the problem persists.
>> I had reflowed all connections except those of X3, so I removed L33
>> and R116 to do so. Everything appears to be well connected and I
>> don't see any shorts.
>>
>> I checked the DC voltages on U11 using the internal probe and have
>> the following values:
>>
>> Pin 1: 1.4
>> Pin 2: 1.4
>> Pin 3: 0.0
>> Pin 4: 4.8
>> Pin 5: 4.8
>> Pin 6: 5.6
>> Pin 7: 5.0
>> Pin 8: 6.0
>>
>> I used the RF probe to check the voltages with the following results:
>>
>> U11, pin 6: 0.74
>> TP2: 0.024
>>
>> The DC voltages for U11 pins 6 and 7 are a bit low and the RF probe
>> values are on the edges. Is it possible that U11 is bad?
>>
>> 73,
>>
>> Craig
>>
>>
>> On 18 Feb, 2007, at 10:46, Craig Young wrote:
>>
>>> Hello to the group.
>>>
>>> I am currently working through the Alignment and Test, Part II and
>>> have run into the following issue. When I perform the BFO Test, I
>>> don't get the proper range. The set of values I get are:
>>>
>>> BFO High Freq.: 4917.31 kHz
>>> BFO Low Freq.: 4916.97 kHz
>>> Range: 0.34 kHz
>>>
>>> The documentation states that if the BFO range is less than 3.6
>>> kHz, the varactor diodes (D37 and D38) or the crystals (X3 and X4)
>>> may be incorrect. However, I've verified them and they are
>>> correct. I've also gone around looking for bad soldering (cold
>>> joints or bridges) and didn't see anything obvious. I've checked
>>> the resistors and capacitors in the BFO section and they appear to
>>> be correct.
>>>
>>> Does anyone have any ideas of where I should look next?
>>>
>>> 73,
>>>
>>> Craig AC6NN
>>>
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