The Yaesu FT-847 includes the capability to extend the sensitivity of the transceiver through the installation of optional filters. The YF-115C is a 500 Hz Collins Mechanical Filter for Morse transmissions (CW), and the YF-115S-02 is a 2.5 kHz Collins Mechanical Filter for single sideband transmissions (SSB). Installation of the filters is similar to the installation of additional memory in a personal computer.
Disconnect the FT-847's power source and carefully turn the transceiver upside down so that the bottom of the case is facing up and the rear of the case is facing away from you.
Remove the two screws located in front of the pop-up stand, the two screws holding the carrying handle to the case, the two screws on the opposite side of the case, and the single screw holding the case to the rear panel. This screw is located close to the cooling fan. Place the screws to the side.
Remove the case carefully and set aside.
Locate the mounting positions for the filters. The mounting position for the YF-115C is the largest furthermost right vertical open slot in the transceiver. The mounting positions for the two YF-112S-02 filters are the smaller vertical open slot and the horizontal open slot located near the centre of the transceiver.
Carefully handle the filters and gently snap them into place in its respective slots. You should seat the filters firmly.
Replace the case and reattach to the chassis using the screws you set aside during the disassembly. Do not overtighten.
Reconnect the FT-847 power supply. If you have installed the YF-115C filter, enter the menu mode by pressing the "Menu" button and rotating the "Sub Tune" dial until menu item number 33 displays. Use the Mem/VFO CH to rotate the menu option to "On," and press the "Menu" button to confirm the selection.
Ensure you are not statically charged by touching a metal object before disassembly. Static discharges can potentially damage the circuitry of the filter.