K3 Build Questions
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I am on pages 44 and 45 of the assembly manual and have made it through all the steps. In going through the resistance checks, I got the following values:
- At the power poles (12VDC), all I got was an infinite resistance no matter which way I made the measured it. - At the R36 test point, I got 239.5 ohms which beats the 150 ohm criteria listed - At the U12 test point, I got 2 different values: a) 4.86 kilo-ohms at the terminal furthest from the blue electrolytic capacitor in the neighborhood of the U12 regulator b) 237.2 ohms at the terminal closest to the blue electrolytic capacitor in the neighborhood of the U12 regulator - At the U13 test point, I got the following: 423 ohms. Question: Am I okay to go ahead and apply power for the initial power on check (aka "smoke test") on page 46? Please advise 73 Steve KC2VNI |
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Steve,
The instructions indicate that the listed values are the lowest that should be measured. The instructions state that greater values than those listed are quite probable. If the readings are not less than the listed values, all is OK. Greater than means that larger values are OK - smaller values are bad. - yours are OK. 73, Don W3FPR KC2VNI wrote: > I am on pages 44 and 45 of the assembly manual and have made it through all > the steps. In going through the resistance checks, I got the following > values: > > - At the power poles (12VDC), all I got was an infinite resistance no matter > which way I made the measured it. > > - At the R36 test point, I got 239.5 ohms which beats the 150 ohm criteria > listed > > - At the U12 test point, I got 2 different values: > a) 4.86 kilo-ohms at the terminal furthest from the blue electrolytic > capacitor in the neighborhood of the U12 regulator > b) 237.2 ohms at the terminal closest to the blue electrolytic capacitor > in the neighborhood of the U12 regulator > > - At the U13 test point, I got the following: 423 ohms. > > > Question: Am I okay to go ahead and apply power for the initial power on > check (aka "smoke test") on page 46? > > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Don: I was concerned with the value on U12. Depending on which terminal I was on, the resistance varied. I should have been more specific about the question. Sorry for the confusion.
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Also, I should have noted that I could not get a reading at the 12VDC side at all and that concerned me. Any significance there?
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In reply to this post by KC2VNI
Steve,
The only resistance reading that is defined in the manual is the regulator terminal furtherest from the electrolytic capacitor - and that measurement was OK. 73, Don W3FPR KC2VNI wrote: > Don: I was concerned with the value on U12. Depending on which terminal I was > on, the resistance varied. I should have been more specific about the > question. Sorry for the confusion. > > > Don Wilhelm-4 wrote: > >> Steve, >> >> The instructions indicate that the listed values are the lowest that >> should be measured. The instructions state that greater values than >> those listed are quite probable. If the readings are not less than the >> listed values, all is OK. >> >> Greater than means that larger values are OK - smaller values are bad. - >> yours are OK. >> >> 73, >> Don W3FPR >> >> KC2VNI wrote: >> >>> I am on pages 44 and 45 of the assembly manual and have made it through >>> all >>> the steps. In going through the resistance checks, I got the following >>> values: >>> >>> - At the power poles (12VDC), all I got was an infinite resistance no >>> matter >>> which way I made the measured it. >>> >>> - At the R36 test point, I got 239.5 ohms which beats the 150 ohm >>> criteria >>> listed >>> >>> - At the U12 test point, I got 2 different values: >>> a) 4.86 kilo-ohms at the terminal furthest from the blue electrolytic >>> capacitor in the neighborhood of the U12 regulator >>> b) 237.2 ohms at the terminal closest to the blue electrolytic >>> capacitor >>> in the neighborhood of the U12 regulator >>> >>> - At the U13 test point, I got the following: 423 ohms. >>> >>> >>> Question: Am I okay to go ahead and apply power for the initial power on >>> check (aka "smoke test") on page 46? >>> >>> >>> >>> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> >> >> > > > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.725 / Virus Database: 270.14.147/2628 - Release Date: 01/17/10 02:35:00 > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by KC2VNI
Steve,
An infinite resistance *is* a valid reading, and is OK. 73, Don W3FPR KC2VNI wrote: > Also, I should have noted that I could not get a reading at the 12VDC side at > all and that concerned me. Any significance there? > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Thanks Don, just wanted to make sure. I am not using a Fluke meter but a cheap one from Radio Shack. When I saw that value was 3K, that's what raised my eyebrows.
I'll let you know how I made out.
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In reply to this post by KC2VNI
Thanks for your responses. I believe I should be okay to turn it on. Please keep in mind that I am not using the best meter (a Radio Shack unit) and it takes a while for the reading to settle down (whether I took the reading in an auto-range or a setting of the specific ranges needed). Typically, the Fluke meters I've used in my process control work are much quicker to settle down (but it's probably because the measuring circuits used are better than what you can expect from Radio Shack for the money I paid). I've not built electronic circuits before and I am obviously concerned that I don't want to inadvertantly set fire to $3K of fine equipment or hurt myself. Next "obvious question" for you: I got an Astron power supply (RS35M) and it is rated for 13.8V about 35amps if memory serves. a) Based on the Owner's Manual page 8, it states that I need about 6A @13.8VDC for the 10W unit (you don't put in the 100W option until later in the build). Do you adjust (in some fashion) the amount of current output needed from the power supply? (I've not gotten the Astron power supply yet- it is hopefully arriving today). I'd think that the answer to my question is "no" as the radio "knows" how much current it needs but once again-it's better to ask. Safety I am working at a grounded outlet (120VAC). Is there anything else I need regarding bonding/grounding for either the radio itself, me, or the power supply? I realize that these are very elementary questions, but better to be safe than sorry. 73 Steve KC2VNI |
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In reply to this post by KC2VNI
I got my power supply, plugged it in and made the connections. No problems at all. The display lit up and diode D33 lit up as well.
It was quite empowering to see the thing take 13.8VDC knowing that I put it together. Looking forward to finishing the build. I will be back to you should I have further questions. |
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