[Elecraft] KRC2 silkscreen gotcha

[Rich]

My issue is getting mine to work with an Icom as a band decoder for my 
band pass filter.  At one time it worked great with my Pro III, but I 
cannot get it to work with the 7300.   Elecraft provided help to no 
avail either.   Everything checks out fine.

Rich

On 11/19/2020 18:41 PM, Paul Fletcher wrote:
> Should be fine - you don’t have the issue I had.
>
>
>> On 19 Nov 2020, at 23:37, Rich <rwnewbould at comcast.net 
>> <mailto:rwnewbould at comcast.net>> wrote:
>>
>> Well I have a negative voltage on U2 pin8 but it is 3 volts higher 
>> than the manual.   Probably not an issue
>>
>> Rich
>>
>> On 11/19/2020 16:58 PM, Paul Fletcher wrote:
>>> The circuit diagram and the parts placement in the manual are 
>>> correct. On mine it was the silkscreen for R12 and R13 that was 
>>> reversed. Let Jack do some digging as it’s possible (from his 
>>> comments) that this doesn’t affect all boards. Mine only arrived a 
>>> few days ago. The easy way to check if there is an issue is to check 
>>> there is the correct negative voltage on pin 8 of U2. Mine was 
>>> almost 0V before swapping the resistors.
>>>
>>>> On 19 Nov 2020, at 21:41, Rich <rwnewbould at comcast.net 
>>>> <mailto:rwnewbould at comcast.net>> wrote:
>>>>
>>>> Thanks for the info.   Could you post the correct value of R12 and R13?
>>>>
>>>> Mine was back at Elecraft way back.   I want to make sure it is 
>>>> already not corrected
>>>>
>>>> Based on your info R12 should be 47ohm, correct?
>>>>
>>>>
>>>> Thanks
>>>>
>>>> Rich
>>>>
>>>> On 11/19/2020 15:52 PM, Paul GACEK via Elecraft wrote:
>>>>> Hi Paul
>>>>>
>>>>> Thanks for the heads up.
>>>>>
>>>>> I had some communication issues with my KRC2 in that it worked 
>>>>> like a champ with my K2 but not so with my KX3.
>>>>>
>>>>> I’m going to crack open my krc2 shortly and see what values I have 
>>>>> in those two resistor locations.
>>>>>
>>>>> What radio where you using with the KRC2?
>>>>>
>>>>> Paul
>>>>> W6PNG/M0SNA
>>>>> www.nomadic.blog <http://www.nomadic.blog/>
>>>>>
>>>>>> On Nov 19, 2020, at 12:47 PM, Wes <wes_n7ws at triconet.org> wrote:
>>>>>>
>>>>>> Thanks.  I've owned one of these for years and as I recall, it's 
>>>>>> always been a problem so it's been resigned to the junk box.
>>>>>>
>>>>>> Maybe I can resurrect it to make it useful for something.
>>>>>>
>>>>>> Wes  N7WS
>>>>>>
>>>>>>> On 11/19/2020 12:58 PM, Paul Fletcher via Elecraft wrote:
>>>>>>> FAO anyone who's had issues getting the serial comms working on 
>>>>>>> a KRC2:
>>>>>>>
>>>>>>> R12 and R13 are transposed on the silkscreen on the PCB. I fell 
>>>>>>> foul of this
>>>>>>> when I recently built my KRC2 and it wouldn't communicate. After 
>>>>>>> quick probe
>>>>>>> around it was evident there was no negative voltage to the RS232 
>>>>>>> driver, U2.
>>>>>>> A little further probing revealed no 12V present at R13 but 
>>>>>>> there was at
>>>>>>> R12. It was then I realised the component layout in the manual 
>>>>>>> is different
>>>>>>> to that marked on the PCB. A quick swap of resistors and 
>>>>>>> everything works as
>>>>>>> it should.
>>>>>>>
>>>>>>> I've re-read the errata and the manual and there is no reference 
>>>>>>> to this
>>>>>>> issue. Apologies if it's been flagged up on here already but I 
>>>>>>> couldn't find
>>>>>>> anyone pointing this out though there do seem to be a few people 
>>>>>>> with serial
>>>>>>> comms issues with the KRC2.
>>>>>>>
>>>>>>> Hopefully this is of assistance to someone.
>>>>>>>
>>>>>>> 73 Paul M1PAF
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