FT8800 memory:

[g0nxi]

My FT8800 works fine, but I am having a problem to get it to remember settings when I set up the CTCSS coding.  After programming the radio, if I switch off it loses the programmed data. I have looked inside for either a battery or large Farad capacitor and not seeing either. 3 emails later to Yaseu UK and no response I am stuck as to how the memory is executed. Can anyone please advise me on this.
TIALes/G0NXI