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