The fuses are marked "ICP-N50" (F-4, F-5) and "ICP-N70" (F1 - F3).
Those are IC protectors that are through-hole soldered to the board. They are short out on overcurrent and then reset. The unit does not have user service parts inside and unfortunately you cannot experiment with fuses.
Those are IC protectors that are through-hole soldered to the board. They are short out on overcurrent and then reset. The unit does not have user service parts inside and unfortunately you cannot experiment with fuses.

