++++++++++++++++++++++++++++++++++++++++++++++++++ Date: Sat, 3 Mar 2001 20:10:52 EST From: DolfinDon at aol.com Subject: [Elecraft] [EleCraft] K1 Pot end play (slop?) Hi All Wayne is right the Bourns pot is a quality part and should not have the amount of end play every has been talking about. I decided to solve this problem on my K1. I had several 10 turn pots with metal shafts in my spare parts bin (junk box). I measured the end play with a dial indicator. The metal shaft parts measured about .003 in. The K1 pot measured about .012 to .014 in. Then I removed the K1 pot and noticed the pot was not setting square with the front panel. The nylon washer on the pot shaft is too small to set flush against the pot and mounts under a bind warping the pot's plastic bushing. The warped bushing forms an oval causing the "slop" in the shaft. OK here's the fix. Remove the pot and washer. Using a rat tail file or a sharp knife carefully enlarge the washer so it will fit flush against the pot. Reinstall per the manual and carefully tighten the pot nut checking the end play. tighten only to the point the end play is removed. If you go too far the pot shaft will be too tight and bind. If this happens back off a little until the shaft is free. My K1 knob now feels as good as my K2 absolutly no end play (slop) is noticeable as you would expect from EleCraft. (Less than .001 in.). EleCraft should check into the washer size problem and supply a little larger washer for this pot (It looks like the small ridge at the base of the pot threds is a little larger on the plastic shaft pot). Hope this helps 73s Don Brown kd5ndb +++++++++++++++++++++++++++++++++++++++++ Date: Sun, 04 Mar 2001 07:21:19 -0800 From: Timothy Gordish Subject: Re: [Elecraft] [EleCraft] K1 Pot end play (slop?) Thanks Don! This fixed the problem with slop in my rig. I found the nylon washer to be too small so I got out the old Dremel tool and router bit and made it slightly larger to fit. Works great, last a long time. Tim ++++++++++++++++++++++++++++++++++++++++++++ Date: Thu, 08 Nov 2001 18:05:15 -0800 From: Wayne Burdick Subject: [Elecraft] Re: K1: 10-turn pot Hi Tim, A very small amount of "wobble" is normal in any plastic-shaft component, even a 10-turn pot. There's a much more expensive metal-shaft/metal bushing version of the pot available from the manufacturer if you feel the need for K2-like stiffness. 73, Wayne N6KR +++++++++++++++++++ Date: Fri, 9 Nov 2001 06:33:25 -0500 From: "Hayden" Subject: [Elecraft] K1 10turn Pot part number The one I got was Mouser PN 652-3540S-1-104. This one has a metal shaft and no side to side slop. It cost $10-15 for the part and the shipping, and I got it in a few days (some months ago). Mike AK3F K1#522 +++++++++++++++++++ Date: Fri, 9 Nov 2001 07:39:08 -0600 From: "Peter Wollan" Subject: [Elecraft] Re: K1: 10-turn pot shaft wobble Tim, Mine wobbled enough that I wrote to Elecraft and asked about it -- the answer was basically don't worry, the part has proved to be durable in practice and the wobble doesn't seem to have any electrical consequences. Some people put a washer, felt or nylon, behind the knob to steady it. Recently there was a post with pictures of a disassembled pot. The shaft moves a slider which provides the electrical contact -- the wobble is between the shaft and the slider, not between the slider and the wires. Peter N8MHD +++++++++++++++++++ Date: Sat, 10 Nov 2001 08:49:52 -0800 From: lhlousek Subject: [Elecraft] K1 10 turn VFO pot The VFO knob on my K1 rocked and wobbled and it got worse with use. It had no significant effect on the performance but it certainly did not convey a level of refinement or quality commensurate with what lay behind the knob. The 10 turn pot supplied with the K1 is the Bourns plastic shaft/bushing 3590 series ($11.08). Bourns also makes a metal shaft/bushing version of the 3590 ($12.98). The radial play specification for the shaft is the same for both versions and I have heard that they have about the same subjective degree of wobble. The Bourns 3540S series ($13.50) has a metal shaft/bushing with about 1/2 the specified radial play of the 3590 series pots. I have one of these on my K1 and it feels like it has about the same play and wobble as the rotary encoder on the K2, i.e. very little. An additional benefit is that inward axial loads are supported by a retaining ring on the shaft that bears against the front of the bushing unlike in the 3590 where the load is borne by the rear of the housing. At least one K1 owner has had the back of the pot get punched out when the VFO knob was pushed or bumped while being transported in baggage. The 3540S should be much stronger. This pot seems to have a slightly greater "wirewound" feel to it than the 3590 series. That is, you can feel the wires through the knob a little more and hear the wiper as it rides over of the windings of the resistive element a little easier. IMO this is an acceptable tradeoff for the much more solid feeling knob. The prices above are single piece prices from the Mouser catalog. The Mouser stock number is 652-3540S-1-104. Lou W7DZN +++++++++++++++++++ ate: Tue, 13 Nov 2001 21:24:40 -0700 From: Tim and Nancy Logan Subject: [Elecraft] Followup: K1 10-turn pot wobble Hi folks - A few days ago I asked about K1 owners' experience with a bit of wobble in the ten-turn pot. The feedback I got convinced me that: 1) yes, there is a bit of wobble in all these pots but 2) it makes no difference at all to the functioning of the K1 and is a perfectly good part. However, being a bit obessive/compulsive (unlike anyone in HAM hi hi), I took Lou, W7DZN's, advice and ordered a a Bourns 3540S series which has a metal shaft and a load bearing retainer on the front of the pot. This pot is as tight as can be and feels great....installs in just a few minutes......no more wobble at all. So if you're a maniacal perfectionist - this is the pot for you. Again, it's only a luxory item - Elecraft's pot is perfectly good and guaranteed. Just thought I'd report back...have a nice evening all. 73/Tim Logan KB7OEX/AE +++++++++++++++++ From: "Don Brown" To: , Subject: Re: [Elecraft] K1 Main Tuning Knob Date: Mon, 14 Apr 2003 07:00:45 -0500 Hi You can make the knob fit closer to the panel by removing the nylon washer on the back of the pot and replacing it with a pot nut like the one on the front. Thread the rear nut on so the front nut has a minimum depth. Cutting the shaft will not do much because the knob will bottom out against the nut although cutting about 1/16 inch may help. I use the Bourns precision metal shaft pot on my K1's (Mouser # 652-3540S-1-104) This pot has a much nicer feel and is more rugged. It costs about $15 and comes with a pot nut and lock washer so you can use the nut and washer that comes with it on the back. Don Brown KD5NDB ----- Original Message ----- From: To: Sent: Monday, April 14, 2003 3:35 AM Subject: [Elecraft] K1 Main Tuning Knob > Greetings Elecraft Wise Ones > > I've just finished the assembly of my K1 front panel. No problems but I > notice that the back of the main VFO tuning knob is further off the front > panel than I would have expected maybe as much as 1/4 inch. It seems to be > fitted on the shaft of the pot as far as it will go. I'm tempted to cut a > bit off the pot shaft with a junior hacksaw but don't want to damage the > pot. Do I have a pot with a longer shaft than most? > > 73 > Martin (M0KWV) +++++++++++++++++