Re: [Elecraft] Small got-ya to watch for when doing the K3 12VDC Out Current Mod
Thankyou Alan, I guess for those like the OP and probably myself, that don’t like to get into the insides without a good reason; Running the K3 at 15v (HD pwr cable too) works out great esp with all the other benefits, hence my observation to those hesitant to do the mod. Adrian ... vk4tux -Original Message- From: Alan Bloom [mailto:n...@sonic.net] Sent: Monday, 10 September 2012 3:58 PM To: vk4tux Cc: elecraft@mailman.qth.net Subject: Re: [Elecraft] Small got-ya to watch for when doing the K3 12VDC Out Current Mod On Sun, 2012-09-09 at 20:50 -0700, vk4tux wrote: Ok, I was thinking the P3/SVGA drew less current at 15v than 12v, due to the 5/3.3/2.5/2.2 v pwr supply setup requiring less current at 15v input than it does at 14v input or less. That's right. I checked the K3 output with a 20 ohm/50w variable rheostat and it trips at 0.6amp or 600mA on my fluke 87. With a 15V supply, the P3 current is probably low enough that it will run OK from the DC output jack of an unmodified K3. The modification is still worthwhile (1) so that the P3 will still work if you (or someone else) tries to run it on a lower-voltage supply, and (2) because the modification reduces the voltage drop to the DC output jack. Alan N1AL What most people notice is that the P3 will switch off after a period of operation when the resettable fuse finally heats enough to open. Your K3 may have a defective resettable fuse in the 12V output line. -- View this message in context: http://elecraft.365791.n2.nabble.com/Small-got-ya-to-watch-for-when-do ing-the-K3-12VDC-Out-Current-Mod-tp7562356p7562362.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] Small got-ya to watch for when doing the K3 12VDC Out Current Mod
I set some time aside this weekend to install a second receiver in my K3, and to perform the 12VDC Out Current Modification since I was adding a SVGA card to my P3 (which requires more current than the stock 0.5 Amp output). My comments pertain to the latter. Elecraft provides the modification kit with the SVGA card and it is very easy in concept, requiring the removal of one SMT diode, and two thru-hole components (a poly-fuse and a choke). The bulk of the time involved is strictly mechanical -- removing covers and sub assemblies to provide clean access to the parts. It was the mechanical aspect that immediately bit me in the backside. My K3 had been lovingly brought to life by the Elecraft factory this January. The first step to the modification is to remove the rear half of the bottom cover. Easy enough, remove 10 screws. The instruction warns you that three of the screws are part of a heat sink assembly which just requires taking care to not lose the washers and other parts attaching the LPA power transistors. However three of the other screws attach to standoffs that are fastened to the main PCB. In my case, unscrewing two of the black pan head screws on the bottom actually caused the hardware attaching the standoffs to unscrew instead, dropping two screws and washer inside the radio. Full stop -- the last thing I wanted to do was flip the radio over and lose those loose parts. So I got eyes on the the loose parts first (as I already had the top cover off for the Aux Receiver install). To avoid this, I would recommend taking the Top Cover off first, then using a screwdriver to tighten down the two screws that are holding the standoffs to the aluminum L-bracket that holds the PA. Then I would remove the fan assembly and PA assembly and tighten the third screw. The LAST thing I would do is remove the bottom cover -- while making sure that the L-bracket screws don't come out (this is the FIRST step in the instruction). My only other observations is use of a good solder sucker (one with high vacuum) is probably helpful for removal of the two leaded components -- otherwise cutting the component body off and removing the leads while heating them might be a good strategy if solder braid is the only available option to remove the remaining solder. The modification would have taken about 30 minutes had the standoffs not come off at the wrong time, and the rework is easy if you have a decent solder sucker. 73, Bob, WB4SON. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Small got-ya to watch for when doing the K3 12VDC Out Current Mod
I have the kit 12v output mod kit still sitting in the shack draw unfitted, and have been running the P3SVGA module first in vk since they started shipping. I have had no issues and run the K3 at 15v. -- View this message in context: http://elecraft.365791.n2.nabble.com/Small-got-ya-to-watch-for-when-doing-the-K3-12VDC-Out-Current-Mod-tp7562356p7562357.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Small got-ya to watch for when doing the K3 12VDC Out Current Mod
What most people notice is that the P3 will switch off after a period of operation when the resettable fuse finally heats enough to open. Your K3 may have a defective resettable fuse in the 12V output line. 73, Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of vk4tux Sent: Sunday, September 09, 2012 7:16 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Small got-ya to watch for when doing the K3 12VDC Out Current Mod I have the kit 12v output mod kit still sitting in the shack draw unfitted, and have been running the P3SVGA module first in vk since they started shipping. I have had no issues and run the K3 at 15v. -- View this message in context: http://elecraft.365791.n2.nabble.com/Small-got-ya-to-watch-for-when-doing-th e-K3-12VDC-Out-Current-Mod-tp7562356p7562357.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Small got-ya to watch for when doing the K3 12VDC Out Current Mod
Ok, I was thinking the P3/SVGA drew less current at 15v than 12v, due to the 5/3.3/2.5/2.2 v pwr supply setup requiring less current at 15v input than it does at 14v input or less. I checked the K3 output with a 20 ohm/50w variable rheostat and it trips at 0.6amp or 600mA on my fluke 87. What most people notice is that the P3 will switch off after a period of operation when the resettable fuse finally heats enough to open. Your K3 may have a defective resettable fuse in the 12V output line. -- View this message in context: http://elecraft.365791.n2.nabble.com/Small-got-ya-to-watch-for-when-doing-the-K3-12VDC-Out-Current-Mod-tp7562356p7562362.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Small got-ya to watch for when doing the K3 12VDC Out Current Mod
On Sun, 2012-09-09 at 20:50 -0700, vk4tux wrote: Ok, I was thinking the P3/SVGA drew less current at 15v than 12v, due to the 5/3.3/2.5/2.2 v pwr supply setup requiring less current at 15v input than it does at 14v input or less. That's right. I checked the K3 output with a 20 ohm/50w variable rheostat and it trips at 0.6amp or 600mA on my fluke 87. With a 15V supply, the P3 current is probably low enough that it will run OK from the DC output jack of an unmodified K3. The modification is still worthwhile (1) so that the P3 will still work if you (or someone else) tries to run it on a lower-voltage supply, and (2) because the modification reduces the voltage drop to the DC output jack. Alan N1AL What most people notice is that the P3 will switch off after a period of operation when the resettable fuse finally heats enough to open. Your K3 may have a defective resettable fuse in the 12V output line. -- View this message in context: http://elecraft.365791.n2.nabble.com/Small-got-ya-to-watch-for-when-doing-the-K3-12VDC-Out-Current-Mod-tp7562356p7562362.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
