[Elecraft] [K2] control board resistance test
Hy to all. Just performed the test as indicated on page 22 of the manual i have 2 values different from ranges indicated. U6 pin 29 indicated 70-90 k i have 96,5 k U6 pin 30 indicated 70-90 k i have 96,7 k Is there anyone (i know he is out there ;D) who can tell me if they are unacceptable values and what to do to solve the problem?? All the other values are good as indicated on the manual. IZ2NYY Giuseppe Pippo Sorrentino Milano ITALY __ 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
Re: [Elecraft] [K2] control board resistance test
Pippo, Check to be certain Control Board RP4 is well soldered. If so, I would believe all is well. Your readings vary by less than 10% from typical, which is usually OK. If your DMM is battery powered, you may want to check for a weak battery which can cause higher than actual resistance readings. 73, Don W3FPR On 10/26/2010 10:00 AM, Giuseppe Sorrentino wrote: Hy to all. Just performed the test as indicated on page 22 of the manual i have 2 values different from ranges indicated. U6 pin 29 indicated 70-90 k i have 96,5 k U6 pin 30 indicated 70-90 k i have 96,7 k Is there anyone (i know he is out there ;D) who can tell me if they are unacceptable values and what to do to solve the problem?? All the other values are good as indicated on the manual. IZ2NYY Giuseppe Pippo Sorrentino Milano ITALY __ 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
[Elecraft] K2-Control Board Resistance Test
First time kit builder and have just completed control board, but resistance checks do not seem to check out for several points: P2, U5, U4 are all okay *Q1 Q2 collectors - both around 29K U6 - pin 8 is okay (about 75K), *U6 - pins 13, 14, are around 40K, U6 - pins 29 and 30 are okay (around 40K) *U8 - pin 2 about 40.7K, pins 15, 16, both 29.3K I have inspected all solder joints with magnifier. I double checked components. What should I do next? Phil, W3HZZ __ 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
Re: [Elecraft] K2-Control Board Resistance Test
Phil, The most likely problem is that you have a solder bridge somewhere (or perhaps several). Look at the amount of solder on your connections. If it has more than a very small fillet, there is too much solder. Actually with the plated through holes just enough solder to fill the holes is sufficient, but I like to see a small fillet on the solder pad. The solder connections should *not* look like 'balls of solder' (with a convex shape), the solder joints should have a concave shape to them. It has been said that a good solder joint looks like a mountain, but not a volcano. Connections that have a concave shape usually indicate that insufficient heat was applied to the solder pad, and the solder did not flow out sufficiently. If you do have too much solder, the cure is to take some away - solder wick works nicely or a professional type de-soldering tool works more quickly. I know it is a lot of work to wick away the excess solder, but if I have described the condition of your Control Board correctly, that is the only positive cure. In the future, heat the solder connection fully so the solder flows out well and control the amount of solder - this is *not* a thing where 'more is better'. A small diameter solder allows better control of the amount applied. 73, Don W3FPR Philip L. Graitcer wrote: First time kit builder and have just completed control board, but resistance checks do not seem to check out for several points: P2, U5, U4 are all okay *Q1 Q2 collectors - both around 29K U6 - pin 8 is okay (about 75K), *U6 - pins 13, 14, are around 40K, U6 - pins 29 and 30 are okay (around 40K) *U8 - pin 2 about 40.7K, pins 15, 16, both 29.3K I have inspected all solder joints with magnifier. I double checked components. What should I do next? Phil, W3HZZ __ 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
