The 817 is a brilliant piece of electronic engineering but like anything it has its faults. Number one on the list would have to be it is not waterproof. Why Yaesu made a rig ultimately suited for portable work and then neglected to make it waterproof I will never know. There are other faults too but the main one is the flimsy power connector, which has given many of its users grief over the years. Finding a replacement power lead has been difficult to start with due to it not being a very common size. The connector you need is 4.0mm outer and 1.7mm inner diameter.
I had wanted two such connectors myself a while ago. One for connecting to a shack power supply and another with Anderson Power Poles to connect to the sealed lead acid batteries I use portable. I had no desire to butcher the one that came with it, that was fitted with a in car type plug that fits into the cigar lighter socket. My good friend Andy MM0FMF came to my rescue as he had bought a load of leads at one time and had a few left.
The latest victim of the of odd sized power connector was blogger Julian G4ILO and it was one of his commentators Graham VE3GTC lead me to The Shoppe at Wulfden and an intriguing solution to wear and tear on the Yaesu FT-817's power connector.
Way back in the June 2005 issue of QST magazine there was an article by Phil Salas AD5X, entitled "Input Voltage Conditioner - and More - for the FT-817". It details a project to add reverse voltage, over voltage, and over current protection, a more convenient power connector (Anderson PowerPoles) and an external voltage regulator to take the much of the heat dissipation from the inside of the rig to the outside. For over five years N1BQ has offering this project as a kit. So far the FT817 community has purchased just under 4000 of these kits at a price that should not break the bank. With this kit failure of the connector is highly unlikely and with the other advantages I wonder how it took so long to come to my attention.