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 SH 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: n...@cds1.net .
Al N1AL
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