Re: [Elecraft] K2 Build #7552 Progress
The four trimmers provided for C32, C34, C44, and C46 are supposed to be 5-30pF ceramics but the ones supplied appear to be quite different. They have a brown plastic type body and don't appear to be ceramic. I can find no markings on the trimmers to indicate their capacitance. The inside adjustment screw head is + shaped rather than a single slot for use with a small flat blade screwdriver. All this makes it difficult to set these trimmers to the mid-point as specified in the manual page 68 Figure 6-23. So I decide to find their midpoint by measuring them before inserting them, but came up with 20 -70pF which is a lot different from the expected 5-30pF. I don't think my capacitance meter would be that far out. The other two 50pF trimmers, C21 and C23 are certainly ceramic. I've checked various assembly photos and they all appear to clearly show ceramic trimmers. Can anyone tell me if these are a correct replacement? Should I proceed to find the measured midpoint of these on the basis that they are a correct replacement? Thanks, Kev VK5KS __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Build #7552 Progress
Kev, Those are the trimmer caps that are currently used. Yes, they are not ceramic, but they have good temperature compensation characteristics (better than the original ceramics). Observe the flat side orientation when installing those capacitors so they can be properly adjusted when using a metallic adjustment tool. If you cannot discern the flat side on the silkscreen, look at the parts placement diagram in the back of the manual. It is not essential that they be set to midpoint, you will be able to easily determine the proper tuning point when you come to the alignment procedure. 73, Don W3FPR On 10/26/2014 2:56 AM, Kevin Schache wrote: The four trimmers provided for C32, C34, C44, and C46 are supposed to be 5-30pF ceramics but the ones supplied appear to be quite different. They have a brown plastic type body and don't appear to be ceramic. I can find no markings on the trimmers to indicate their capacitance. The inside adjustment screw head is + shaped rather than a single slot for use with a small flat blade screwdriver. All this makes it difficult to set these trimmers to the mid-point as specified in the manual page 68 Figure 6-23. So I decide to find their midpoint by measuring them before inserting them, but came up with 20 -70pF which is a lot different from the expected 5-30pF. I don't think my capacitance meter would be that far out. The other two 50pF trimmers, C21 and C23 are certainly ceramic. I've checked various assembly photos and they all appear to clearly show ceramic trimmers. Can anyone tell me if these are a correct replacement? Should I proceed to find the measured midpoint of these on the basis that they are a correct replacement? __ 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 Message delivered to w3...@embarqmail.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] K2 Build #7552 Progress
I have now completed up to the start of Assembly, Part III, P67, with all tests and alignments done. AND BEST OF ALL, it works!! I have actually heard several strong SSB signals on 40M.. YAAYY!! Although I am limited with test equipment, I've managed to pass all tests. But I will hopefully be calling on some higher precision equipment for the final alignment in due course. I think one of the biggest lessons I've learned is not to over compensate for my old soldering skills by minimizing solder too much. Having got the right brand and gauge of solder, and an appropriate temperature compensated iron, this heavy handed old vacuum tube builder became just a little too frugal. Many joints needed an extra touch up during testing, but hey, I'm learning! The only thing i have noticed is that the audio gain does not seem to act as I would expect while listening to an SSB signal - the volume seems to increase marginally from minimum and then stay constant over much of the range before increasing slightly at the end . Maybe this is another case of an extra touch of solder somewhere, or maybe it's a normal function of how the AGC level works? Now, it's on to Assembly Part III, P67!! 73, Kev VK5KS __ 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 Message delivered to arch...@mail-archive.com
