Coincidentally this is exactly what I did Pom last month on my 15 years old (June 2004) battered FT-857, that has done quite a few activations. I don’t use the radio in my shack.
The power leads where they go into the grommet at the back of the radio were chafed and the conductors on both cores were starting to be exposed. The rig is unsaleable anyway due to its external condition and I wouldn’t want to sell it on anyway. I decided therefore to do away with the twin lead, booted connector and fuses completely! I’ll take the chance.
Now there is less to go wrong. I found some substantial enough red and black power lead, drilled out the grommet - the orginal wires are moulded into it with heat I believe, so they wouldn’t just pull out. And I then resoldered the new wires on to the board inside and put some heat shrink sleeving either side of the grommet which should stop any strain on the power cable connections on the circuit board. The plug is now an RC5 radio control modellers plug which fits all the batteries that I use for /P work.
Only used the radio once since on G/DC-008 about 10 days ago. I ran 60 watts and made 34 QSOs with the radio on CW / SSB with no adverse reports. 73 de Phil G4OBK