Toto power plug light

Hi all
I have had a Toto Washlet TCF 426 I bought 4 years ago in Japan which I have run through a step down transformer here in Australia with no issues until now. This week it has developed an issue after the power company cut the power.

The power plug reset button is now lit (never used to be). Each time I try to reset it it springs back and is lit again. My limited Japanese has made it difficult to work out he problem but I assume it is some form of safety switch. I thought there may be a fuse of some sort but could not locate access for one. My step down transformer is fused and RCD-ed so if there was a surge it should have protected it.

Anyone had this issue or has better Japanese that could interpret what the potential solution may be.

Any help appreciated else sounds like I am in the market for a new one.

Thanks

Best place to get the answer :
toto@info.toto.com