Hi Geoff. It is a real puzzler. I have checked the voltages on the encoder and these switch between 4.95V and 100mV when the shaft is rotated slowly, they don't alternate between each other but are in sync. It is possible to change the frequency using the encoder but only by a small amount and only if the shaft is spun quickly.
Resistance readings between the 5V supply pin and the Enc A/B are infinate or beyond the range of my Fluke 77 meter in one polarity and 3.9MOhm in the other. Between Enc A/B it is 8,2MOhm and Infinate when changing polarity. Between 5V pin and Enc-enable it is between 4.2MOhm and infinate when changing polarity Enc A and Enc-enable between 8.15MOhm and infinate when changing polarity. Enc B and Enc- enable between 8MOhm and infinity when changing polarity. All measurements done with the encoder in cct. I have a friend just round the corner from me who is in the process of building a K2 (has been for quite a whlie :-) ) so we have arranged to do some testing this afternoon with his control and display boards. He also has a suitable scope so hopefully I will be able to test the function of the MCU also. I also have a Dataman S4 programmer so the possibility of reflashing the firmware may exist, though this may be a last resort as I wouldn't want to corrupt his radio as well. Again thanks to all on the reflector who have responed. Will update later today once the comparison tests have been conducted. Regards Nidge (G0NIG) IO93dv ----- Original Message ----- From: "Geoffrey Mackenzie-Kennedy" <gm4...@btinternet.com> To: "Nidge (Nigel Smith)" <nig_sm...@o2.co.uk> Cc: "Elecraft Discussion List" <elecraft@mailman.qth.net> Sent: Sunday, April 18, 2010 11:08 AM Subject: Re: [Elecraft] K2 Encoder problems continue. > Nidge, > > Thanks for your reply. > > Unfortunately I do not know enough about Hamradio Deluxe nor its interface > with the K2, but rightly or wrongly I assume that if the radio works > properly under computer control, then the MCU (U6) is working as it should > during this mode of control. > > I cannot shake my hunch that something is pulling down to near ground > either > the ENC A or the ENC B lines (or both) when the MCU is in place. If the > encoder is an optical type, then under such a fault condition I would not > be > too surprised if the voltage on ENC RD also dropped to near ground - which > is what you have measured at U3 pin 14. It would be worthwhile to make > some > resistance measurements between these three lines and ground, with the > power > off - MCU in place and MCU removed. > > Not to be overlooked is the possibility that the fault might be > mechanical. > For instance if a small sliver of solder had worked its way into the MCU's > socket, it might create a short when the MCU chip is in place - but "open" > when the chip is removed. > > Good luck. > > 73, > Geoff > GM4ESD > > > On Saturday, April 17, 2010, at 11:13 PM, Nidge (Nigel Smith) wrote: > >> Hi Don and Geoff >> >> Thanks for the replies both. >> >> First of all Geoff: I'm afraid I don't have a scope here anymore. I did >> remove the MCU >> and checked the voltages, and this time on pin 14 of U3 I had the correct >> voltage close >> to 3.8V, with the MCU inserted it was below 100mV. > >> The radio, when connected to Hamradio Deluxe works fine under computer >> control, both >> on receive and transmit. The filters are off but that's because I'm >> unable >> to fine tune them >> as the encoder isn't working. > > > > > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.801 / Virus Database: 271.1.1/2818 - Release Date: 04/18/10 07:31:00 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
