Replace 6 AA Batteries... Hack a Casio label printer to allow a wall power adaptor, 57 cent module

Tired of having to replace 6 1.5v AA batteries, I've decided to hack my casio label printer (KL-60) to let me use an old monitor power adaptor. Uses a small 57 cent buck converter to drop the voltage to the required 9v.
Buck converter from Aliexpress:
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