Manual: {F15992}
May not be the manual for my revision per se, as setting reverb does not appear to be as mapped, or maybe I'm reading the manual wrong, but the button combo takes me instead to the tuning, which appears to default to 442Hz, [[ https://www.moeck.com/en/service/faq/the-tuning-at-a1-442-hz/ | a compromise between classic 440Hz and modern orchestras maybe ]]?
Other stuff:
* Some patch files and old DOS utilities: http://www.midimusicadventures.com/queststudios/mt32-resource/
* Semi-old Java app: http://www.jsynthlib.org/
I have a real one, but emulation is probably an easier time for most! And https://github.com/dwhinham/mt32-pi uses http://munt.sourceforge.net/ to even provide a cheap dedicated hardware reimplantation.