RE: [Elecraft] Melted J3 Connector on K2/100
Rick K7MW wrote: And a relativly large voltage drop. This would show up as a low voltage at the rig. This is why it is important to monitor the voltage at the rig. If there is an unexpected low voltage at the K2, the cause needs to be determined. -- Very true, and notice Rick said RELATIVELY large voltage drop. A drop of only 1/2 volt, from 13.8 to 13.3 V at 15 amps = 7.5 watts of heat being generated. That's plenty of heat to melt a lot of plastic! I had a similar failure, but in my case it was with the fuse holder. When I got my KPA100, Elecraft finally shorted me a part from a kit. I was missing half of the fuse holder. I was building it over a holiday weekend and, not wanting to delay power-up, I decided not to request and wait for the missing part. There was a auto supply store nearby that surely could supply a suitable in-line fuse holder. Several weeks after finishing my KPA100 and enjoying it on the air I was surprised when my K2 power failed for a moment while transmitting at 100 watts. Then it was fine. A few minutes later power went off again momentarily. I started checking connectors. The Anderson at the back of the rig was fine. The connections to the Astron 20 amp supply under the desk were fine. Then I happened to touch the in-line fuse holder near the power supply. It was HOT! Those fuse holders depend upon spring pressure to hold the contacts against the ends of the fuse. For some reason this automotive fuse holder didn't have good enough contact. The voltage drop was negligible, at least when I had done the initial checkout, but apparently and increased ever so slightly over time. As the resistance grew, so did the heat. The heat was enough to soften the plastic holder. The spring inside holding the contacts tight against the fuse by pushing against the holder caused it to stretch when it got warm, making the contacts poorer and the heat greater until the circuit opened. As soon as it cooled a bit, the contact was regained temporarily. A better quality fuse holder fixed the problem. Ron AC7AC ___ 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
[Elecraft] Melted J3 Connector on K2/100 - Reprise - Part II
Ron and Tom are totally correct. On inspection of the connectors they were not seated forward enough because I tried to do something fancy...like putting two wires coming out of the 20 amp APP to run the KAT100. I did not get the spade pushed far enough into the plastic shell. I will be changing that tomorrow and running one wire into the APP and make sure they are soldered (with they were) but pushed in till they "click." I see now they were not "clicked" into a locking position. I got the black on to click in, but the red one is toast. I will replace both ... and ... run seperate power from the PS to the KAT100. I had this very same thing happen on a 240 Volt AC dryer plug onceand the Fire Department was calledit was smokin'! Poor connection between the plug or the socket and the wire running to the breaker box. Nasty! Lee - K0WA Lee Buller <[EMAIL PROTECTED]> wrote: Date: Mon, 19 Jun 2006 19:57:38 -0700 (PDT) From: Lee Buller <[EMAIL PROTECTED]> To: Elecraft Reflector Subject: [Elecraft] Melted J3 Connector on K2/100 Well, I was giving the K2/100 heck (100 watts) on 40 meters tonight into a nice load (1.2) and things start stinking a little when I turn it back over to the other station. I had been sending code at around 18 wpm for about 10 minutes. I am running a Astron switching power supply. Then the rig shut off and did not come on again. The heat sink was not all that hot, but I noticed the large gauge wire and the fuse holder was warmer than what I would expect. The 20 amp fuse was not blown. I pulled the Anderson Power pole plugsand the RED side of the plug is melted while the black plug is not. The RED Anderson Power Pole connector on the K2 is also slighly deformed from melting. I took the K2 over to another supply on the bench and the K2 came up. Looking at the schmaticI must have drawn to much current for the connectors. Hardly seems to be plausible. What do you experts think here? Lee - K0WA In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some and use it. If you can't find any common sense, ask for help from somebody who has some common sense. ___ 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 In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some and use it. If you can't find any common sense, ask for help from somebody who has some common sense. ___ 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
Re: [Elecraft] Melted J3 Connector on K2/100
So if you melted your Anderson connector, it had unusually high resistance for some reason. Ron AC7AC - And a relativly large voltage drop. This would show up as a low voltage at the rig. This is why it is important to monitor the voltage at the rig. If there is an unexpected low voltage at the K2, the cause needs to be determined. Rick Dettinger K7MW ___ 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 ___ 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
RE: [Elecraft] Melted J3 Connector on K2/100
Lee, KOWA wrote: Well, I was giving the K2/100 heck (100 watts) on 40 meters tonight into a nice load (1.2) and things start stinking a little when I turn it back over to the other station. I had been sending code at around 18 wpm for about 10 minutes. I am running a Astron switching power supply. Then the rig shut off and did not come on again. The heat sink was not all that hot, but I noticed the large gauge wire and the fuse holder was warmer than what I would expect. The 20 amp fuse was not blown. I pulled the Anderson Power pole plugsand the RED side of the plug is melted while the black plug is not. The RED Anderson Power Pole connector on the K2 is also slighly deformed from melting. I took the K2 over to another supply on the bench and the K2 came up. Looking at the schmaticI must have drawn to much current for the connectors. Hardly seems to be plausible. What do you experts think here? --- You should have been drawing something like 15 to 18 amps, peak key down, from the power supply at 100 watts. Sending CW, that's likely something in the range of 10 amps on average (the sending speed has nothing to do with the duty cycle: 2 wpm and 200 wpm with the same Morse text has the same duty cycle). That certainly should not overhead those Anderson connectors or damage the K2. It sounds like it's a problem at the connector, since the rig works FB once you connect it to another cable. The way a cable connector overheats is by the resistance in the connection at the terminals. If the resistance were zero, you could draw millions of amps through it and it'd stay perfectly cool. Unfortunately, the resistance might be very low compared to what we're used to, but it's no where near zero! So there is always some heating of the connector and wire. That's what the amperage rating is based upon for both connectors and wire: the amount of resistance they show. So if you melted your Anderson connector, it had unusually high resistance for some reason. I can think of two reasons for that: 1) What I'd consider the most likely is a bad contact between the two halves of the connector when they were mated. That's easy to make happen with an Anderson connector *if* you fail to push the contacts all the way forward in the housing! If they aren't all the way in, the tabs will just touch over a small area, producing a relatively poor connection that will heat up badly. The KPA100 manual advises making sure the wires cannot be pulled back out. That's one way to ensure the terminals are fully inserted. If you'd like to see photographs of properly (and improperly) inserted Anderson connector terminals, download a copy of the Transverter Assembly Manual for the XV432 Transverter. That's the Assembly Manual, not the XV Owner's Manual. Properly and improperly installed terminals in Anderson connectors are shown in photographs in Figure 27 on Page 33. 2) The other possibility is a bad connection between the cable wire and the terminal in the connector. That's why the manual advises soldering, not just crimping, the cable to the connector. A little bit of resistance right there can turn the assembly into a powerful heating element that will cause a lot of trouble. Be sure your wires are securely soldered to the terminals. Ron AC7AC ___ 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
[Elecraft] Melted J3 Connector on K2/100
Well, I was giving the K2/100 heck (100 watts) on 40 meters tonight into a nice load (1.2) and things start stinking a little when I turn it back over to the other station. I had been sending code at around 18 wpm for about 10 minutes. I am running a Astron switching power supply. Then the rig shut off and did not come on again. The heat sink was not all that hot, but I noticed the large gauge wire and the fuse holder was warmer than what I would expect. The 20 amp fuse was not blown. I pulled the Anderson Power pole plugsand the RED side of the plug is melted while the black plug is not. The RED Anderson Power Pole connector on the K2 is also slighly deformed from melting. I took the K2 over to another supply on the bench and the K2 came up. Looking at the schmaticI must have drawn to much current for the connectors. Hardly seems to be plausible. What do you experts think here? Lee - K0WA In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some and use it. If you can't find any common sense, ask for help from somebody who has some common sense. ___ 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
