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KRC2 silkscreen gotcha

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KRC2 silkscreen gotcha

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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Wes Stewart-2

Re: KRC2 silkscreen gotcha

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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Help: http://mailman.qth.net/mmfaq.htm
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Elecraft mailing list

Re: KRC2 silkscreen gotcha

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

> On Nov 19, 2020, at 12:47 PM, Wes <[hidden email]> 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
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Elecraft mailing list

Re: KRC2 silkscreen gotcha

Hi Paul,

I’ve not used it with a radio yet, this was to communicate with a PC to configure the KRC2 (though the same issue would apply to anything using RS232). The KRC2 wasn’t responding at all hence the start of fault finding and the findings I posted. As soon as the resistors were corrected everything worked as it should without issue.

Hope this helps.

73 Paul M1PAF

> On 19 Nov 2020, at 20:52, Paul GACEK via Elecraft <[hidden email]> 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 <[hidden email] <mailto:[hidden email]>> 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
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft <http://mailman.qth.net/mailman/listinfo/elecraft>
>> Help: http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm>
>> Post: mailto:[hidden email] <mailto:[hidden email]>
>>
>> This list hosted by: http://www.qsl.net <http://www.qsl.net/>
>> Please help support this email list: http://www.qsl.net/donate.html <http://www.qsl.net/donate.html>
>> Message delivered to [hidden email] <mailto:[hidden email]>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Elecraft mailing list

Re: KRC2 silkscreen gotcha

In reply to this post by Elecraft mailing list

After seeing this report I pulled the Rev C PCB (the only PCB we have shipped for this product) and took a good look at it, then looked at the docs and finally the Gerbers for the board.
R12 and R13 on the KRC2 PCB are properly labelled. R12, closest to the switches, is a 4.7K ohm resistor (yellow-violet-red) used to pull the RS232 line to -12V.
R13 is next to it, closest to the DE9 connectors is a 47 ohm resistor (yellow-violet-black) and provides +12V power for the JFET.
The legends on the PCB and in Figure 10 of the KRC2 Rev C manual are correct.

Now, what caused you to think they were backwards? And, let’s make sure that you do have a Rev C board in your KRC2.

73,
Jack, W6FB

> On Nov 19, 2020, at 11:58 AM, Paul Fletcher via Elecraft <[hidden email]> 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
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Gordon LaPoint

Re: KRC2 silkscreen gotcha

In reply to this post by Elecraft mailing list

I have two KRC2's, one uses the aux-bus line with a K3 and the other
uses the RS232 with a Kenwood TS590sg. The only problems I have had are
all self induced with programing errors!
They both work flawlessly and have for years, one drives a WX0b Six Pak,
the other drives a MFJ RCS-20Lx switch.
Gordon - N1MGO

On 11/19/2020 16:26 PM, Paul Fletcher via Elecraft wrote:

> Hi Paul,
>
> I’ve not used it with a radio yet, this was to communicate with a PC to configure the KRC2 (though the same issue would apply to anything using RS232). The KRC2 wasn’t responding at all hence the start of fault finding and the findings I posted. As soon as the resistors were corrected everything worked as it should without issue.
>
> Hope this helps.
>
> 73 Paul M1PAF
>
>> On 19 Nov 2020, at 20:52, Paul GACEK via Elecraft <[hidden email]> 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 <[hidden email] <mailto:[hidden email]>> 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
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft <http://mailman.qth.net/mailman/listinfo/elecraft>
>>> Help: http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm>
>>> Post: mailto:[hidden email] <mailto:[hidden email]>
>>>
>>> This list hosted by: http://www.qsl.net <http://www.qsl.net/>
>>> Please help support this email list: http://www.qsl.net/donate.html <http://www.qsl.net/donate.html>
>>> Message delivered to [hidden email] <mailto:[hidden email]>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Rich-4

Re: KRC2 silkscreen gotcha

In reply to this post by Elecraft mailing list

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
>
>> On Nov 19, 2020, at 12:47 PM, Wes <[hidden email]> 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
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Elecraft mailing list

Re: KRC2 silkscreen gotcha

In reply to this post by Elecraft mailing list

I have a Rev C PCB and the silkscreen does not match the diagram in the Rev C manual. On the PCB R12 and R13 are marked the opposite way round to the manual. I can send pics if you want them.

> On 19 Nov 2020, at 21:33, Jack Brindle <[hidden email]> wrote:
>
> After seeing this report I pulled the Rev C PCB (the only PCB we have shipped for this product) and took a good look at it, then looked at the docs and finally the Gerbers for the board.
> R12 and R13 on the KRC2 PCB are properly labelled. R12, closest to the switches, is a 4.7K ohm resistor (yellow-violet-red) used to pull the RS232 line to -12V.
> R13 is next to it, closest to the DE9 connectors is a 47 ohm resistor (yellow-violet-black) and provides +12V power for the JFET.
> The legends on the PCB and in Figure 10 of the KRC2 Rev C manual are correct.
>
> Now, what caused you to think they were backwards? And, let’s make sure that you do have a Rev C board in your KRC2.
>
> 73,
> Jack, W6FB
>
>> On Nov 19, 2020, at 11:58 AM, Paul Fletcher via Elecraft <[hidden email]> 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
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>

Elecraft mailing list

Re: KRC2 silkscreen gotcha

Please do. Also, please also send a picture of the label on the bottom side closest to the front of the device.

Jack, W6FB
Elecraft Engineering

> On Nov 19, 2020, at 1:47 PM, Paul Fletcher <[hidden email]> wrote:
>
> I have a Rev C PCB and the silkscreen does not match the diagram in the Rev C manual. On the PCB R12 and R13 are marked the opposite way round to the manual. I can send pics if you want them.
>
>> On 19 Nov 2020, at 21:33, Jack Brindle <[hidden email]> wrote:
>>
>> After seeing this report I pulled the Rev C PCB (the only PCB we have shipped for this product) and took a good look at it, then looked at the docs and finally the Gerbers for the board.
>> R12 and R13 on the KRC2 PCB are properly labelled. R12, closest to the switches, is a 4.7K ohm resistor (yellow-violet-red) used to pull the RS232 line to -12V.
>> R13 is next to it, closest to the DE9 connectors is a 47 ohm resistor (yellow-violet-black) and provides +12V power for the JFET.
>> The legends on the PCB and in Figure 10 of the KRC2 Rev C manual are correct.
>>
>> Now, what caused you to think they were backwards? And, let’s make sure that you do have a Rev C board in your KRC2.
>>
>> 73,
>> Jack, W6FB
>>
>>> On Nov 19, 2020, at 11:58 AM, Paul Fletcher via Elecraft <[hidden email]> 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
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to [hidden email]
>>
>

Elecraft mailing list

Re: KRC2 silkscreen gotcha

In reply to this post by Rich-4

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 <[hidden email]> 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
>>
>>> On Nov 19, 2020, at 12:47 PM, Wes <[hidden email]> 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
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to [hidden email]
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email] <mailto:[hidden email]>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft <http://mailman.qth.net/mailman/listinfo/elecraft>
> Help: http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm>
> Post: mailto:[hidden email] <mailto:[hidden email]>
>
> This list hosted by: http://www.qsl.net <http://www.qsl.net/>
> Please help support this email list: http://www.qsl.net/donate.html <http://www.qsl.net/donate.html>
> Message delivered to [hidden email] <mailto:[hidden email]>

Rich-4

Re: KRC2 silkscreen gotcha

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 <[hidden email]
>> <mailto:[hidden email]>> 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 <[hidden email]> 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
>>>> ______________________________________________________________
>>>> Elecraft mailing list
>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>> Post: mailto:[hidden email]
>>>>
>>>> This list hosted by: http://www.qsl.net
>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>> Message delivered to [hidden email]
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered [hidden email]
>>> <mailto:[hidden email]>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home:http://mailman.qth.net/mailman/listinfo/elecraft
>> <http://mailman.qth.net/mailman/listinfo/elecraft>
>> Help:http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm>
>> Post:mailto:[hidden email] <mailto:[hidden email]>
>>
>> This list hosted by:http://www.qsl.net <http://www.qsl.net/>
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>> Message delivered [hidden email] <mailto:[hidden email]>
>

Elecraft mailing list

Re: KRC2 silkscreen gotcha

Should be fine - you don’t have the issue I had.

> On 19 Nov 2020, at 23:37, Rich <[hidden email]> 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 <[hidden email] <mailto:[hidden email]>> 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 <[hidden email]> <mailto:[hidden email]> 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
>>>>> ______________________________________________________________
>>>>> Elecraft mailing list
>>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft <http://mailman.qth.net/mailman/listinfo/elecraft>
>>>>> Help: http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm>
>>>>> Post: mailto:[hidden email] <mailto:[hidden email]>
>>>>>
>>>>> This list hosted by: http://www.qsl.net <http://www.qsl.net/>
>>>>> Please help support this email list: http://www.qsl.net/donate.html <http://www.qsl.net/donate.html>
>>>>> Message delivered to [hidden email] <mailto:[hidden email]>
>>>> ______________________________________________________________
>>>> Elecraft mailing list
>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft <http://mailman.qth.net/mailman/listinfo/elecraft>
>>>> Help: http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm>
>>>> Post: mailto:[hidden email] <mailto:[hidden email]>
>>>>
>>>> This list hosted by: http://www.qsl.net <http://www.qsl.net/>
>>>> Please help support this email list: http://www.qsl.net/donate.html <http://www.qsl.net/donate.html>
>>>> Message delivered to [hidden email] <mailto:[hidden email]>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft <http://mailman.qth.net/mailman/listinfo/elecraft>
>>> Help: http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm>
>>> Post: mailto:[hidden email] <mailto:[hidden email]>
>>>
>>> This list hosted by: http://www.qsl.net <http://www.qsl.net/>
>>> Please help support this email list: http://www.qsl.net/donate.html <http://www.qsl.net/donate.html>
>>> Message delivered to [hidden email] <mailto:[hidden email]>

Rich-4

Re: KRC2 silkscreen gotcha

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 <[hidden email]
>> <mailto:[hidden email]>> 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 <[hidden email]
>>>> <mailto:[hidden email]>> 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 <[hidden email]> 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
>>>>>> ______________________________________________________________
>>>>>> Elecraft mailing list
>>>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>>>> Post: mailto:[hidden email]
>>>>>>
>>>>>> This list hosted by: http://www.qsl.net
>>>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>>>> Message delivered to [hidden email]
>>>>> ______________________________________________________________
>>>>> Elecraft mailing list
>>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>>> Post: mailto:[hidden email]
>>>>>
>>>>> This list hosted by: http://www.qsl.net
>>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>>> Message delivered [hidden email]
>>>>> <mailto:[hidden email]>
>>>> ______________________________________________________________
>>>> Elecraft mailing list
>>>> Home:http://mailman.qth.net/mailman/listinfo/elecraft
>>>> <http://mailman.qth.net/mailman/listinfo/elecraft>
>>>> Help:http://mailman.qth.net/mmfaq.htm
>>>> <http://mailman.qth.net/mmfaq.htm>
>>>> Post:mailto:[hidden email] <mailto:[hidden email]>
>>>>
>>>> This list hosted by:http://www.qsl.net <http://www.qsl.net/>
>>>> Please help support this email list:http://www.qsl.net/donate.html
>>>> <http://www.qsl.net/donate.html>
>>>> Message delivered [hidden email] <mailto:[hidden email]>
>>>
>

Wes Stewart-2

Re: KRC2 silkscreen gotcha

In reply to this post by Wes Stewart-2

After writing this, I dug it out and without removing the board to inspect just
powered it up and measured Pin 8 of U2 and found -8 something V. So I guess
it's okay.

Wes N7WS

On 11/19/2020 1:45 PM, Wes 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

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