Hi Scott,
Operating System on MicroArranger is PA50, but it is brand new wheras PA500 has been around for at least 2 maybe even 3 years.
There again microarranger manual doesn't mention SDHC either, yet they work??

Quote
"Data storage 8MB (>20MB equivalent) Internal Solid State Disk (SSD), SD/MMC card slot."


Plot Thickens.
Originally Posted By: Scottyee
My Korg microARRANGER is essentially a Pa50,
which is older than the Pa500.
My Sandisk brand 8 GB SDHC Card works great with my Korg microARRANGER
so I would expect it would work on the Pa500 as well.
I was advised that formatting the SD/SDHC card on the keyboard itself critically important.
I was also recommended to purchase Sandisk to assure compatability.

Scott
_________________________
best wishes
Rikki 🧸

Korg PA5X 88 note
SX900
Band in a Box 2022