++++++++++++++++++++++ Date: Wed, 29 May 2002 15:02:58 -0700 From: Phil Wheeler Organization: Outstanding To: Joe Malloy Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] K1 problems and questions! Joe Malloy wrote: > >Well, I figure I've got some sort of intermittent. So's I check various >things and don't see anything left unsoldered, solder bridges, or what not. >Next, I check the KFL1-4 -- no obvious errors; so I pull out the resistance >check on page 15 in the KFL1-4 manual and lo and behold, many of the reading >don't jive with the manual. In particular, U1 pin 13, P2 pin 6 shows open >and the rest of U1 readings (except U1 Pin 1 and U1 pin 2) read infinite >instead of 360-440 ohms. > Joe, Make sure you are looking at the correct pins. U1-13 and P2-6 are connected by a 100 ohm resistor. That should not be open unless R1 has failed open. And -- make these measurements with the KFL1-4 removed from the radio. BTW -- I had a similar problem that developed over a 3 day period on 20 M -- went from 7 W output to 2-3 W. I did a re-alignment and have since replaced my original Wht trimmers by Blue ones (just today in fact). 73, Phil +++++++++++++++++ Date: Wed, 29 May 2002 15:35:09 -0700 From: Phil Wheeler Organization: Outstanding To: "Timothy A. Raymer" Cc: Joe Malloy , elecraft at mailman.qth.net Subject: Re: [Elecraft] K1 problems and questions! Timothy A. Raymer wrote: > Joe, > > I think Phil is on the right track. When I read your problem, I was > going to recommend giving the ceramic trimmer capacitors a few good > twists, and then doing a realignment on the K-1. I think that may > help you out. > > Phil, I am curious which brand of trimmers you chose to replace the > white ceramic ones. It's a standard Elecraft replacement kit for early KFL1-4s, Tim. See: http://www.elecraft.com/Apps/KFL1_4_Temp_range.htm There are two available fixes. I replaced the trimmers (Method 2) because several were very pressure sensitive in aligment and I am in a very stable thermal environment (SoCalif, one mile from the ocean). And my 20 m output had dropped dramatically in a 4-5 day period. So I figured it was time to bite the bullet. Later KFL1-4s had the newer trimmers, I believe. But I think I got the first one shipped, or close to it. I just finished and did the alignment and it feels much more stable. 73, Phil ++++++++++++++++++ From: "Stuart Rohre" To: "Phil Wheeler" , "Timothy A. Raymer" Cc: "Joe Malloy" , Subject: Re: [Elecraft] K1 problems and questions! Date: Wed, 29 May 2002 17:44:43 -0500 Hi all, For folks living near a salt water environment, do not overlook the possible accumulation of salt upon dielectric insulators lowering the power of the circuit. This could happen in the K2, if you do not have air conditioned shack, or it could happen driving an outdoor antenna, if the salt air got to the plastic or ceramic insulators of an antenna. I have had to wash off outside insulators at beach portable locations when this happened. Especially bad on days when you have a wind blowing in from off shore. GL and 72, Stuart K5KVH ++++++++++++++++++++++ Date: Wed, 29 May 2002 15:52:32 -0700 From: Phil Wheeler Organization: Outstanding To: Stuart Rohre Cc: "Timothy A. Raymer" , Joe Malloy , elecraft at mailman.qth.net Subject: Re: [Elecraft] K1 problems and questions! Not my problem at least, Stuart -- my symptoms were with a dummy load. Flaky trimmers in the early KFL1-4 kits are a problem well-known to Elecraft; in fact, Gary pointed me to the replacement approach, since mine were especially bad (and had been very sensitive during alignment from the git-go). 73, Phil Stuart Rohre wrote: >Hi all, >For folks living near a salt water environment, do not overlook the possible >accumulation of salt upon dielectric insulators lowering the power of the >circuit. This could happen in the K2, if you do not have air conditioned >shack, or it could happen driving an outdoor antenna, if the salt air got to >the plastic or ceramic insulators of an antenna. I have had to wash off >outside insulators at beach portable locations when this happened. >Especially bad on days when you have a wind blowing in from off shore. >GL and 72, >Stuart K5KVH ++++++++++++++++++++ Date: Wed, 29 May 2002 16:02:29 -0700 From: Phil Wheeler Organization: Outstanding To: ac7a at gci-net.com Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] K1-4 receiver sensitivity problem Thomas, I just re-aligned my K1 after changing all 16 trimmers (Work!) and=20 noticed what you say here: >A possible hint: The pre-mix band-pass filters all peaked >the receiver gain. The trimmers in the receiver side of the >RF band-pass filter (CA, CC, CE, and CG) peaked the gain as >well. However, the corresponding filter trimmers CB, CD, >CF, and CH, all behaved as though there wasn=92t a peak. > in my case, too. But the latter trimmers do have a definite peak in TX=20 alignment. One thing: Make sure you have the jumper from Pin to to Pin 10 of J2.=20 Otherwise, you will not have an antenna connected to hear noise from=20 . An easy mistake: As many times as I have aligned my K1, I just=20 made that mistake today. 73, Phil ac7a at gci-net.com wrote: >Hello, > >I am in the process of assembling a 4-band, K1 transceiver, >and have ran into a bit of a problem with the receiver >performance. This has been observed at the receiver >alignment procedure.=20 > >The problem is very poor receiver sensitivity. In fact, >only the strongest of signals can be detected. This is the >case on all bands. The audio gain is very good, so it looks >like a RF or IF signal problem. > >A possible hint: The pre-mix band-pass filters all peaked >the receiver gain. The trimmers in the receiver side of the >RF band-pass filter (CA, CC, CE, and CG) peaked the gain as >well. However, the corresponding filter trimmers CB, CD, >CF, and CH, all behaved as though there wasn=92t a peak. >These trimmers are on the T/R, antenna path side of the >filter. > >Can anyone tell me if CB through CH exhibit broad peaks >that don=92t seem to affect the gain very much?=20 > >I am interested in any other ideas you may have with regard >to the sensitivity problem as well. > >Thanks, Thomas =96 AC7A (Tucson) > ++++++++++++++++ From: "Joe Malloy" To: Subject: RE: [Elecraft] K1 problems and questions! Date: Thu, 30 May 2002 17:29:20 -0400 Ok, guys, I return with further info on my plight. First, a shame-faced confession: I royally screwed up the pinout of U1 on the KFL1-4, so naturally the resistances didn't check out. When I finally got the board and the pins properly identified, all was normal and fine. The problem, methinks, is indeed the capacitors on the rf board -- when rotated some, they work to a certain extent then -- poof! -- they quit. I've contacted Elecraft, ordered the replacements and am anxiously awaiting them. Let's see: I ordered them yesterday, received email confirmation of my order about three hours later (what *took* them so long! :) and they weren't here today. Ok, maybe that's unrealistic. I check the mail tomorrow. (I'm only kidding, of course, I can't expect Elecraft HQ to improve the USPS!). I'll report on the replacements probably next week or so. Thank you *all* for your suggestions -- whether right on the money or not, they were all welcome and proof positive that this list is one of the great features of buying an Elecraft rig. Muchas gracias! Grazie! Vielen Dank! 73, Joe, W2RBA ++++++++++++++++++++ Date: Sun, 02 Jun 2002 09:41:47 -0700 From: lhlousek Subject: Re: [Elecraft] KFL1-4 Trimmer Cap Replacement To: elecraft at mailman.qth.net I replaced all the trimmers on my KFL-4 with no difficulty. It was well worth the effort because my K1 would lose more than half its power on some bands with a ambient temp decrease of only 10 F (75 to 65 F) with the old caps. The new caps totally eliminated the temp sensitivity of the power output over the range 40F to 100F. I left all the solder on, heated one leg at a time, and used a dental pick to pull up one side of the trimmer at a time being very careful to insure that the solder was melted on both sides of the PCB before pulling. I then used a solder sucker to remove the solder. >From past experience, I feel that if you use solder wick to remove the solder first, you lessen the heat conductivity to the top of the PCB and create a greater risk of damaging the PCB. It also works well to heat the joint from the same side you are pulling if you can get the iron in there. Obviously this method works only when you can remove one lead at a time either because of the type of component or because you have clipped all the leads. Lou W7DZN ++++++++++++++++