Try resoldering the connections to the MCU socket. Look at connections with a magnifier, and heat and add a bit of solder to any that look grainy or otherwise not good.
The fact that it worked partially and then stopped working suggests a flaky solder joint rather than a wiring mistake! On 10/24/2012 9:10 PM, AC8HU wrote: > Hi all - > > Started build of my K2 a few weeks back and have been slowly progressing. I > must say I'm not an overly experienced builder - I've built a number of > smaller kits, the largest being an MFJ shortwave regen receiver and one of > the "Ice Tube" clocks you can find online - but all of my builds thus far > have ended with success. Through Part 1 of the RF board tests, all was > well. Upon reaching the part 2 tests, things appeared to be fine as well (4 > MHz Oscillator Calibration checked out ok, and PLL Reference Oscillator > Range Test was fine as well). However when I proceded to the VCO Test, the > problems started - with the first appearance of the Info 080 message. I've > had no luck in fixing the problem since. Here's what I've found/checked: > > 1.) X2 on the control board is the proper crystal - I was able to hear it > on another receiver and zero-beat it by adjusting C22 > 2.) Resistance between pin 28, U1 (RF board) and pin 40, U6 (control board) > is 197 to 198 ohms - well below the 900 to 1000 it should be > 3.) Voltage on pin 28 of U1 (RF) is 0.14 V (close to 0, certainly nowhere > near the 5-6 V range) - this apparently indicates that U1 is not programmed > AND that the Aux Bus is open, although I've had no luck figuring out where > the problem is with the Aux Bus > 4.) Checked voltage on pin 32 of the MCU (U6, control board) and found it > to be exactly 5 V - checks haven't indicated any problems with the MCU I can > find > 5.) I currently have no relay sound at startup. I did previously (even > with the first few startups of the Part 2 tests) however sometime after > these problems started, the relay activity stopped. > 6.) Checking pins 1 and 20 of U1 on the RF board both give me 6 V > 7.) Measuring pin 28 of U1 to ground with power off gives me a high > resistance value > > I attempted a "456" reset as I've seen mentioned elsewhere - this seemed to > do no good as following the 10 seconds of Info 201 message, instead of the > "Elecraft" message, I got the Info 080 message again. Pressing any button > to continue past that results in a display of 00000.00 and what looks like > part of the number 2, NOT the c to indicate CW mode. I assume this is a > result of U1 not properly communicating with U6 at this point. > > Any suggestions? At this point I'm fairly certain I have a fried (or > "unprogrammed") U1, but I suspect I've got some other problem as well. (I > have been using an anti-static mat and wrist strap while building, however > my soldering iron itself isn't grounded and perhaps should be.) I'm quite > the novice in terms of electronics so I can't really interpret the numbers > I'm seeing other than to compare them to the baselines and see where things > aren't correct. Not totally discouraged at this point, but definitely > distressed... > > Thanks in advance for your help! > > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/Info-080-message-started-with-RF-Alignment-and-Test-Part-II-tp7564545.html > Sent from the Elecraft mailing list archive at Nabble.com. > ______________________________________________________________ > 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 -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ ______________________________________________________________ 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
