Sansui AU 607 Alpha MR Integrated Amp FUSE QUESTION

I just purchased this Amp . I always check fuse for correct values.
..however, I cannot find the fuse in this amp.
Are there fuses in this amp ?...and where would they be located?
It has good relay protection when I turn unit on.
I noticed when I removed cover, that there was a small amount of rust inside....should I be concerned.
Is there anyone familiar with this model?....It was sold in Japan only.
Thanks