Elecraft AF-1 Errata -external power labels reversed

Discussion in 'Radio Circuits, Repair & Performance' started by W3KW, Nov 30, 2019.

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  1. W3KW

    W3KW Platinum Subscriber Platinum Subscriber QRZ Page

    I just built the Elecraft AF-1 Filter. Its a nice build, and very effective. I built it for specific use with the Heathkit HW-8. I am adding a zero beat indicator (grandfather of zero beat), and the DNR filter from Sotabeams. All packaged in a clear, waterproof enclosure. I've off-mounted at the I/O and discovered the power pins, labeled 1 and 2 are reversed. Looking at ythe board, you'll see pin 1 goes to the anode side of the protection diode (+) but the directions label this as (-). I also installed the power jack to the board as supplied. This caused a short when using external power, blowing the fuse in my DC distribution strip so I removed the jack. Problem solved. The jack was shorted internally. Maybe during installation? Maybe I got it too hot? Either way, it works perfectly now.

    Next, I think I need to install a switch to select external power, or internal power, respectively.

    I'll add some photos.



    AF-1 Back.jpg

    AF-1 Schematic power section.jpg

    AF-1 Board Trace side.jpg

    AF-1 Board Component Side.jpg

    More to come when complete.

  2. W3KW

    W3KW Platinum Subscriber Platinum Subscriber QRZ Page

    upload_2019-12-8_14-59-28.jpeg Well, all done. I added the grandfather of zero beat and the AF-1 is a handy tool for older rigs without sufficient filtering. Pins 1 and 2 are silk screened reversed so use caution when off-mounting connectors like I did.




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