[Yaesu] FT-857D low-power/battery mode: no fans!

[494]

Okay, I'm sure y'all already know this, but I was happy to find out that you can stop the FT-857D's cooling fans from blowing during every transmission, and instead only blow when they're needed. The manual that I have only mentions that "battery mode" reduces the RF power out, and says nothing about the fans (unless I missed something).

All you have to do is short the brown lead in the power harness to ground, and I did this with a very thin piece of enameled copper (ends stripped) jumping from the metal crimp for the brown wire to the metal crimp of the black wire at the end of the plastic Molex power connector nearest the transceiver. (You'll have to slide away the heat-shrink shroud.) The jumper is easily removable for QRO operation, and if it shorts accidentally I believe the wire is tiny enough to act as a fast-acting fuse. (Although I've cut the wire short enough so that a power-supply short should be all but impossible.)

As advertised, this jumper limits your transmit power to 20W on HF and 10W on UHF (per the manual) but instead I don't have to listen to the nosy fans during every transmit and for a few seconds after unkeying. I operate under 20W more than 95% of the time anyway, so this is ideal for me, as the blower noise was easily my biggest complaint about the 857D; so much so that I was considering taking the whole darn thing apart and installing my own thermostat on the heatsink. I'm glad I didn't do that! Anyway, I just wanted to share.

Thanks for the bandwidth,
Nick Hecker (KI4YSP) South Carolina