Hi NASAMike,
you don't need a .
ppi file (from a SINGLE Pack)!
A .
ppi file can be DIRECTLY installed on the keyboard, BUT all other, previous installed Expansion content will be DELETED from the keyboard's Expansion Wave memory.
What you need is the latest version (2.5.3) of the Yamaha Expansion Manager program (YEM), installed on your PC or Mac.
Then export the "Instrument Info" file (.n27) from your Keyboard to a USB stick (in "[FUNCTION] → TAB [F] MENU 2 → [G] SYSTEM → TAB [E]
OWNER" display.
Now connect the USB stick to the PC/Mac and import the "Instrument Info" file to the YEM (as "Install Target").
Then import the .
ppf file to YEM: Select "Import Pack" by clicking the PLUS sign near "My Packs".
Click on your "Install Target" (the PSR-S970) on the left side. Make sure all the Packs you want to install on the S970 have a LIGHT GREEN checkmark. (If NOT click on the checkmark again).
Then click on "Save as Pack Install File" button to save your
personal .
ppi file to the connected USB stick.
Connect the USB stick to the keyboard, press "[FUNCTION] → TAB [F] MENU 2 → [F] PACK INSTALLATION", select your Pack Installation file (.ppi) on the USB stick and press "[6 down] (INSTALL)"
To select the installed Expansion voices later, press [EXPANSION / USER] button (or open the Voice Selection display in another way and go to USER tab and Expansion folder). Each Pack has his own folder there.
Hope this helps!
P.S.
Patrick was faster, because I was interrupted while writing my posting ...
Best regards,
Chris