Bill, I would wager that the choke is actually open. This is one place where you cannot readily detect an open choke by measuring the voltage on each side of it. Turn power off and measure the resistance, and I believe you will see that it is open.
If you have another 100 uH choke that will fit, just replace it. Even Elecraft has switched to a larger choke I believe just because many folks have damaged the tiny one when bending the leads. If you do not have a 100 uH choke available, temporarily jumper across it until you can obtain a replacement choke. 73, Don W3FPR > -----Original Message----- > > Update. > > 1. Tom (N0SS) suggested I redo the CAL PLL. Done. No effect. > > 2. Jim (K4ZM) suggested I.... > > > Check the resistance of the small 100uh rfc that you added > between 16 and > > the +12 volt line. I have seen this same problem when that RCF > is open. > > It is a very delicate choke and very easy to break the wire inside the > > choke. An easy way to test it is to measure the dc voltage on > both sides > > of the rfc and if the voltage is not the same then you probably > have a bad > > RFC. > > ..so I popped the bottom and took a look. On the rail (which is not 12v, > btw), I read 5.02V, > and on the other side of the 100uH I read 4.23V... not the "same", but I > assume that's the > choke wire resistance. Along the same vein, I also remembered > that someone > else attributed > this issue to the added LC circuit (as part of the A-B version update): > > http://www.ac6rm.net/mailarchive/html/elecraft-list/2003-08/msg00424.html > > So I took the blade of my screwdriver and shorted the 100uH inductor > (RFC15).... warble is gone! > > So, questions: > > Are the L-C comps "hard-linked"? i.e. if I remove this mod, is there any > benefit to leaving the cap, > or should I remove both parts? Should I try a different 100uH instead? I > don't think I ever had the > 7128 warble, so I installed these as a precaution only. > > Any ideas on why this LC circuit is the culprit (might want to > look at this > since there is at least two confirmed cases now)? > > As Wayne suggested in the included link, I also checked the value > of R19 and > it was fine. > > Bill > W1PA > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
