Actually, I was looking for this information for 3 years!...now thanks to you, the manual is on my hands and of great help, cause I understand now where I was doing wrong connections and wires...excellent, I'll be back to you if in need, thank you.
This manual covers the main equipment features only. While it also includes the procedure for saving and loading from the now long obsolete memory cards it does not mention the how to operate with the optional floppy drive interface so I am still at a loss about how to use this! Note that there is a separate manual covering the MIDI interface and programming via the keyboard, not included in this download. You will also need to get hold of this if you want to use the MIDI interface properly. Basically there is little difference between this manual and the free to download manual for the similar PR60 model.
Good list of manuals. I found a very rare one and easily get. Should be promptly to download, as we must to wait hours even after confirmed payment.
Text excerpt from page 47 (click to view)
Initializing Sheet Battery
You can initialize the sheet battery in the same way as the standard battery pack, but you cannot initialize the sheet battery only. The standard battery will be initialized at the same time if you start initializing process. It will take about 12 to 15 hours to complete initializing process.
Removing Sheet Battery
1. 2. 3.
Turn off the computer and the peripheral devices. Remove the AC adapter and peripheral devices. Loosen the screws counterclockwise.
Take the sheet battery off the computer and close the cover of the sheet battery port. Check the power remaining of the standard battery or connect AC adapter to the computer before removing the sheet battery. Otherwise the computer will be shut down and data may be lost.