K2 troubleshooting
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I SHOULD be embarrassed by my mistakes...but, I figure, I am learning
more electronics in the last few months than I ever did in my early years. So, I really don't mind sharing them with the group. Hope the group doesn't mind. Here's the latest news: Yes, as noted before I found errors relating to confusing 560 designation and 561 and 820 designation and 821. I found the "evil twins" tonight: C228 was a 561 (supposed to be 560) and C210 was a 821 (supposed to be 820) So C4 is now correct (821) and C12 is correct (561) I will get the right caps for C228 and 210 and start alignment over. Now, as I was reviewing solder joints, etc., I noted that one of the solder pads for C4 was touching the outer can tab of L1. My question: Is this a solder bridge, or is there supposed to be a connection between C4 pad and outer (ground) tab of L1? I looked on N0SS's PCB pix and I cannot tell if a connection exists there or not. (thanks, by the way, to Tom for the pix). John AB8WH _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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John:
Don't use the pictures for this, use the schematic. There you'll see that one end of C4 is grounded, as is the can of L1. best wishes, dave belsley, w1euy On Jun 7, 2006, at 9:05 PM, John Wiener wrote: > I SHOULD be embarrassed by my mistakes...but, I figure, I am > learning more electronics in the last few months than I ever did in > my early years. So, I really don't mind sharing them with the > group. Hope the group doesn't mind. > > Here's the latest news: > > Yes, as noted before I found errors relating to confusing 560 > designation and 561 and 820 designation and 821. > I found the "evil twins" tonight: C228 was a 561 (supposed to be > 560) and C210 was a 821 (supposed to be 820) > > So C4 is now correct (821) and C12 is correct (561) > I will get the right caps for C228 and 210 and start alignment over. > > Now, as I was reviewing solder joints, etc., I noted that one of > the solder pads for C4 was touching the outer can tab of L1. > My question: > > Is this a solder bridge, or is there supposed to be a connection > between C4 pad and outer (ground) tab of L1? > I looked on N0SS's PCB pix and I cannot tell if a connection exists > there or not. (thanks, by the way, to Tom for the pix). > > John > AB8WH > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com ------------------------------------- david a. belsley professor of economics _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by John Wiener
John,
Yes, one side of C4 is grounded (see the schematic). With 40 meters selected, check the resistance to ground on both C4 leads - if you find ground on both leads, look for the solder bridge. If you have higher than zero ohms on one lead, all is well. Note that if you do not select 40 meters and power off before doing the resistance checks, you will certainly find both leads grounded (through the relay contacts) 73, Don W3FPR > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]]On Behalf Of John Wiener > Sent: Wednesday, June 07, 2006 9:05 PM > To: Elecraft email > Subject: [Elecraft] K2 troubleshooting > > > I SHOULD be embarrassed by my mistakes...but, I figure, I am learning > more electronics in the last few months than I ever did in my early > years. So, I really don't mind sharing them with the group. Hope > the group doesn't mind. > > Here's the latest news: > > Yes, as noted before I found errors relating to confusing 560 > designation and 561 and 820 designation and 821. > I found the "evil twins" tonight: C228 was a 561 (supposed to be > 560) and C210 was a 821 (supposed to be 820) > > So C4 is now correct (821) and C12 is correct (561) > I will get the right caps for C228 and 210 and start alignment over. > > Now, as I was reviewing solder joints, etc., I noted that one of the > solder pads for C4 was touching the outer can tab of L1. > My question: > > Is this a solder bridge, or is there supposed to be a connection > between C4 pad and outer (ground) tab of L1? > I looked on N0SS's PCB pix and I cannot tell if a connection exists > there or not. (thanks, by the way, to Tom for the pix). > > John > AB8WH > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.394 / Virus Database: 268.8.2/357 - Release Date: 6/6/2006 > > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by John Wiener
Hi John:
>Now, as I was reviewing solder joints, etc., I noted that one of the >solder pads for C4 was touching the outer can tab of L1. >My question: > >Is this a solder bridge, or is there supposed to be a connection >between C4 pad and outer (ground) tab of L1? >I looked on N0SS's PCB pix and I cannot tell if a connection exists >there or not. (thanks, by the way, to Tom for the pix). Fast answer... YES! They're supposed to be touching. Here's how to use the pic to help... that is, IF you have a suitable graphics program (or viewer): 1) Load both the TOP and BOTTOM views of the PC board in question. 2) LOCATE the component(s) in question of the side of the PC board which includes the silkscreened nomenclatures. 3) ENLARGE the (TOP SIDE) image so that most of your screen is occupied by the component pads in question. 4) ENLARGE the BOTTOM SIDE image to the same size. 5) FLIP the TOP SIDE image HORIZONTALLY. Of course, now all the print is reversed, but you should be able to re-locate the components in question by merely SLIDING the image right or left (flipping side to side usually won't cause the image to move up/down). 6) Make the image FULL SCREEN. 7) Switch to the BOTTOM SIDE image and (using the relative scroll bar positions of the drag bars from the TOP SIDE image) position the bottom side image so you can place the pads for the component in question immediately beneath those of the TOP SIDE image. You can usually use CTRL-TAB to toggle between the two images, so you can easily tell if the two sets of pads are aligned, one above the other. 8) With the two images properly aligned, you can now quickly switch between top/bottom views in order to get a really CLOSE look at the pads and land connections between them. I use this method all the time when doing signal path tracing on the PC board itself. In regard to your particular question, if you find a case where it appears that two pads are touching, check both top and bottom. If the pads appear to be so close together that they'd almost have to be touching, it's a pretty guess that they're supposed to be that way... especially given that NO OTHER UN-CONNECTED pads are anywhere nearly as closely spaced. Finally, check out the schematic!!! If (as it does in this case) the schematic indicates that one end of C4 connects to L1 AND to ground, then you've just answered your question WITHOUT having to resort to the images. All the images do then is to confirm that one end of C4 is attached to the (grounded) metal cover lug of L1, and that one end of L1 is also connected at the same point. Since the reflector doesn't support file attachments, I'm sending you some blown-up images of the parts of the PC board in question. 73, Tom Hammond N0SS _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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