Casiotone 401 (CT-401) transformer

This keyboard is supposed to be working - i bought it from a flea-market. So this isn’t so much a repair as an adjustment for testing.

I’m not new to buying old things and repair/re-use for something else - like building my own synth and wiring it up to the keyboard matrix … but it would obviously be much nicer to keep it working.

So on the rear of it there is AC120 and serial number for an IEC male AC kettle plug. The previous owner was warning you need a transformer but this is Thailand. Anyway, i’ve swapped out Jap100v transformers in a record player (technics) to make it work directly on Thai power. I’m Australian - we always use 230-240v.
Yes, I know I can get a step-down transformer but in my experience there is a danger there of someone forgetting to use it and boom.

I included a pic of transformer - before I mess with it - i want advice. It has 220v and 100v written on it but on the step-down side it has a lot of wires - clearly many taps for different voltage or different coils. Its a very big transformer for 35w. Is there this possibility that I can just wire it up to be 220v input coil?

Anyone got a schematic?
Thanks for any help/advice

Update: So i guess it does indeed take different input AC voltage

On the underside of this plug feeding the power plug rails through to the transformer is a multi-selector … but I don’t know which direction is which. So all that I have now is some kind of problem-solving… what kind of resistance on the coil (or impedance I guess) is going to be the higher voltage. Maybe I’ll get

So pointing to the right is the set voltage and the higher resistance is on the higher voltage. So I put it on 240 and powered it up and its going. Now it has other digital issues - random continuous notes playing. Fun but not fun.
Better start testing connections and things I guess …