The MFJ-4125 "PowerLite" power supply is a great little unit for the price
(around $100). It puts out 13.7V at 25A in a small, light package that is perfect for portable operation with the K3 or K2. Unlike some other switching supplies, it has very low electrical noise. Unfortunately the same can't be said for acoustic noise. The loud fan is the one thing people complain about. So I designed a fan controller that reduces the fan voltage for normal operation while running it at full speed when the internal heat sink warms up. I've posted an article on my web page: http://www.cds1.net/~n1al/ham/fan_controller.htm I have enough parts left over to build 4 more units. If anyone is interested I can supply a kit of parts for $5 postpaid/USA that includes the clamp and all electrical parts except for the TIP-29 power transistor. (I'll throw in a TIP-31 from my junk box that that should work the same, or you can obtain the exact part yourself.) I also have a couple PC boards left over that I'll include while they last. Email me if you're interested: [hidden email] . Al N1AL ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
I had 13 replies from people wanting to build my fan controller for the
MFJ power supply, but unfortunately I only had enough spare parts for four units. Fortunately, the parts are easy to get (Digi-Key part numbers are listed on the web page listed in my original message, copied below). The PC boards are available for $4.00 plus S&H from FAR Circuits, or will be as seen as I send the film artwork back to Fred KF9GX, owner of FAR Circuits. http://www.farcircuits.net/ Refer to the "BLOOM FAN CONTROL BOARD". Thanks to everyone for their interest. Al N1AL > The MFJ-4125 "PowerLite" power supply is a great little unit for the price > (around $100). It puts out 13.7V at 25A in a small, light package that is > perfect for portable operation with the K3 or K2. Unlike some other > switching supplies, it has very low electrical noise. > > Unfortunately the same can't be said for acoustic noise. The loud fan is > the one thing people complain about. So I designed a fan controller that > reduces the fan voltage for normal operation while running it at full > speed when the internal heat sink warms up. I've posted an article on my > web page: > http://www.cds1.net/~n1al/ham/fan_controller.htm > > I have enough parts left over to build 4 more units. If anyone is > interested I can supply a kit of parts for $5 postpaid/USA that includes > the clamp and all electrical parts except for the TIP-29 power transistor. > (I'll throw in a TIP-31 from my junk box that that should work the same, > or you can obtain the exact part yourself.) I also have a couple PC > boards left over that I'll include while they last. Email me if you're > interested: [hidden email] . > > Al N1AL > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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