K2 C111 installed backwards
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One of the problems with putting pictures of your K2 out on the Web is that
everybody gets a shot at finding your mistakes. Roger, OE6MSF, points out that it appears that I may have installed C111 on the RF board backwards. C111 looks like a filter cap between line 8T and ground. Since 8T isn't used for any Elecraft options, I suspect I may have accidentally picked the right cap to install backwards. Any opinions to the contrary? I'm eventually going to open this thing up and install some more options so I'll eventually fix it. Any reason to panic about this and fix it now? Craig NZ0R K1 #1966 K2/100 #4941 _______________________________________________ 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 |
RE: K2 C111 installed backwards
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Craig,
C111 is an electrolytic capacitor, and if subjected to reverse voltage it can overheat and rupture. Since it only has voltage on it during transmit periods, it may take some time, but yes, change it before it explodes on you. True the 8T signal is not used for any of the options, but it IS used internally in the K2, so it does have voltage on it (only during transmit, but still ...). 73, Don W3FPR > -----Original Message----- > > One of the problems with putting pictures of your K2 out on the > Web is that > everybody gets a shot at finding your mistakes. > > Roger, OE6MSF, points out that it appears that I may have > installed C111 on > the RF board backwards. C111 looks like a filter cap between line 8T and > ground. Since 8T isn't used for any Elecraft options, I suspect I may have > accidentally picked the right cap to install backwards. > > Any opinions to the contrary? I'm eventually going to open this > thing up and > install some more options so I'll eventually fix it. Any reason to panic > about this and fix it now? > > _______________________________________________ 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 |
Re: K2 C111 installed backwards
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Sounds like *someone* hasn't gone through that formative experience in
electronics .... installing an electrolytic cap backwards and turning on the juice. It can be very entertaining, if a bit smelly, at times! 73 de Alex nS6y On Feb 4, 2006, at 2:24 PM, Don Wilhelm wrote: > Craig, > > C111 is an electrolytic capacitor, and if subjected to reverse voltage > it > can overheat and rupture. Since it only has voltage on it during > transmit > periods, it may take some time, but yes, change it before it explodes > on > you. > True the 8T signal is not used for any of the options, but it IS used > internally in the K2, so it does have voltage on it (only during > transmit, > but still ...). > > 73, > Don W3FPR _______________________________________________ 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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I recall building a transmitter many years ago using a good old 807, anyway
I put one of the caps the wrong way round on the HT side and when the transmitter was fired up it was like one of those party poppers going off! Never did find the aluminum can that was part of it! Lots of nice oily paper floating around thou ! Good luck and hope it all goes well for you Paul M0BMN On Feb 4, 2006, at 2:24 PM, Don Wilhelm wrote: > Craig, > > C111 is an electrolytic capacitor, and if subjected to reverse voltage > it > can overheat and rupture. Since it only has voltage on it during > transmit > periods, it may take some time, but yes, change it before it explodes > on > you. -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 267.15.1/250 - Release Date: 03/02/2006 ___________________________________________________________ Yahoo! Photos – NEW, now offering a quality print service from just 8p a photo http://uk.photos.yahoo.com _______________________________________________ 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 |
RE: K2 C111 installed backwards
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In reply to this post by Don Wilhelm-3
I'll get it fixed before transmitting again. I have lots of hours of
transmit time including some intense contest periods and no explosions yet but I'll get it replaced. Craig -----Original Message----- From: Don Wilhelm [mailto:[hidden email]] Sent: Saturday, February 04, 2006 4:24 PM To: Craig Rairdin; [hidden email] Subject: RE: [Elecraft] K2 C111 installed backwards Craig, C111 is an electrolytic capacitor, and if subjected to reverse voltage it can overheat and rupture. Since it only has voltage on it during transmit periods, it may take some time, but yes, change it before it explodes on you. True the 8T signal is not used for any of the options, but it IS used internally in the K2, so it does have voltage on it (only during transmit, but still ...). 73, Don W3FPR > -----Original Message----- > > One of the problems with putting pictures of your K2 out on the > Web is that > everybody gets a shot at finding your mistakes. > > Roger, OE6MSF, points out that it appears that I may have > installed C111 on > the RF board backwards. C111 looks like a filter cap between line 8T and > ground. Since 8T isn't used for any Elecraft options, I suspect I may have > accidentally picked the right cap to install backwards. > > Any opinions to the contrary? I'm eventually going to open this > thing up and > install some more options so I'll eventually fix it. Any reason to panic > about this and fix it now? > > _______________________________________________ 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 |
RE: K2 C111 installed backwards
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If you have a capacitance tester, it'd be a good idea to check and see if
the capacitor is still a capacitor. Obviously it didn't short, but it might now be open which could cause odd problems down the road if you use that circuit because if the cap is open the circuit is no longer properly bypassed. Electrolytics really HATE to be operated backwards. This one was especially nice to you about it though. It didn't short and nail that circuit to ground. Ron AC7AC -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Craig Rairdin Sent: Saturday, February 04, 2006 5:30 PM To: [hidden email] Subject: RE: [Elecraft] K2 C111 installed backwards I'll get it fixed before transmitting again. I have lots of hours of transmit time including some intense contest periods and no explosions yet but I'll get it replaced. Craig _______________________________________________ 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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