I had to go and buy one of these.
With thanks to Mitzy on Ravelry, I've manage to work out what the little mystery box is, it's a knitleader that lights up the needles to assist with shaping. And no earthy good if you can't read the Japanese instructions. Never mind it's a lovely machine.
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| Mystery box which is an early knit leader - all in Japanese | 
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| Brother KH355 NaNa carraige | 
Thanks to Mitzy again, who found the Japanese method of 
changing the sponge bar. Which I thought would be nice in English. So here's mine
The sponge is enclosed in plastic and is changed from above 
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| The top comes out by pinching the ends | 
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| The tape is on one half of the machine | 
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| and rolls off | 
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| lift up the electronic board and carefully remove the old sponge | 
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| Brushing out the fluff then insert the new sponge | 
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| put the circuit board back into it's clips and line up the lugs at the back and roll forward | 
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| locate the white pegs into their slots, making sure it all lines up and press down | 
 Now my NaNa is ready for a test knit! As far as I can tell, (which means as much as Mitzy could find out for me) it was only made for the Japanese market. But I hope the pictures are interesting.