Looks like the CVP-809 uses another key combination to turn on screenshot mode ...
Another way to take screenshots is sending MIDI SysEx (system exclusive) messages.
On my Genos, the following sequence works (all bytes in hexadecimal notation):
1) Send "7E.7F.09.01" to turn on GM1 mode (General MIDI version 1)
2) Send "43.10.4C.00.00.7E.00" to turn on Yamaha XG mode
3) (optional) Send "90.3C.60" to play a middle C note (#60) on channel 1
4) Send "43.73.01.51.09.00.00.00" to read keyboard screen into an internal buffer
5) Send "43.73.01.51.09.00.02.01.04" to write internal buffer to USB1 root directory as file "CAPT00xx.BMP"
6) (optional) Send "90.3C.00" to turn off the note started in step 3
I have uploaded a small Windows program "SndSysEx.exe" to DropBox.
Here is the link:
https://www.dropbox.com/s/lid09lqcl5jr5pt/SndSysEx.exe?dl=0DropBox might try to talk you into creating an account, but you do not need an account just for downloading !This windows program needs the NET Framework 4.0 runtime (or later) - which should be already installed on all windows versions.
a) To use it, make sure that no other MIDI program is running.
b) Start SndSysEx.exe.
c) In the upper listbox, select "Genos, Tyros3/4" as keyboard type.
d) In the lower listbox, select the MIDI output port - usually "Digital Workstation-1", if you are using the Yamaha USB MIDI driver.
e) Press the button "Send SysEx to create a screenshot".
f) If the MIDI connection works, you should hear a short middle C note.
g) The screenshot named "CAPT00xx.BMP" should be found in the root directory of USB 1 drive.
Update 2022-01-11: - added download link (DropBox)
- Check box to turn on/off playing note while screenshot is taken
- Program window now resizable