eHam
eHam Forums => Boat Anchors => Topic started by: W2JJV on March 16, 2023, 12:43:14 PM
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I currently have a pretty good size muffin fan sitting on top of my KWM-2 above the RF cage and it pulls out a lot of heat but half the time I forget to turn it on (powered separately) and when I need to lift the lid, it's always in the way. Has anyone used the little fan mounted on a pcb that is sold on e-Bay. They just fit under two of the RF cage screws but it does not sit above the cage, rather in the front. Just curious if they are as effective as what I have now?
David W2JJV
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I no longer have any Collins gear, but when I had the KWM-2A, I ran a line from the rear panel 6.3VAC RCA jack into a simple voltage doubler circuit and powered a 12 VDC fan, pretty much like you have now. I encased the circuit in an old 35mm film can. You can use long thin screws (possibly #4? ) through two of the holes in the cover to hold the fan in place, and if the screws are narrow enough, you will not mar the cover. Automatically turn on with fan when the rig is powered on!
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I have a 220v muffin fan over the PA cage on top of the KWM-2A mesh lid, and the fan sits on 4 small rubber feet.
Running the 220v Fan off 110v supply and although quieter , its very efficient.
To open cover I pick up fan, place on table and replace after.
I previously had a very small internal fan, but was very noisy and inefficient.
Another method of cooling I want to try is a 12v DC fan mounted to top cover with very thin screws, and supplying it off the 6.3v rca supply from rear, using a bridge rectifier and 1000uF cap in a small plastic box.
Will give about 9 to 10V DC which is perfect for the 12v Fan.
I did this exact mod on the Heathkit HA-14 and its' the charm!.
73 de William, ZS4L / ZS5WC
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12V muffin fan running from a wall wart. The 80x80 (3x3) size will fit perfectly sitting on top of chassis to left of final compartment. On edge. Just put it there, no brackets, screws, etc. Blows air into final area. Easiest way. Then run the wire out through a nearby big hole in cabinet to wall wart.
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Iused the cooling fan mounted on a pcb inside the cabinet. Worked great, kept the whole interior much cooler. Go Fer it!