My SC-8820 has dead MIDI ports so I am thinking about a software signal reroute. Is it possible, using MIDIOX and MIDI Yoke, to redirect MIDI signals from the soundcard's gameport to an the SC-8820 that is connected to the computer via USB cable?
Are you sure that the SC-8820 'computer' switch is set to MIDI and that a Win98 MIDI application can send MIDI data the Win98 MIDI redirector when it is pointed to the Roland SC-8820 driver provided "SC-8820 synth part A"? IF the physical DIN-5 MIDI ports are "broken", then try the USB port connection method (and switching the 'computer' switch to USB) to see if any Windows MIDI program can produce MIDI output.
The other SC-8820 'computer' switches were for Mac, PC (serial port) and USB (USB v1.0) which of course do not use the DIN-5 MIDI ports.
I mean I am trying to start DOS games under Win98. DOS games only know about MPU-401 so they send MIDI to the soundcard's game port. Can I tap into that signal and send it to "SC-8820 synth part A" ?
Unlike Win2K and WinXP which can redirect the MIDI I/O ports at 0x330 for the NTVDM DOS emulation, Win98 itself does not not hook the MIDI I/O ports at 0x330 for its DOS 'emulation' mode via a system VxD. In its Win98 VxD SoundBlaster drivers for 16-bit ISA sound-cards, Creative did hook the MIDI I/O ports at 0x330 (or 0x300) to allow MIDI data redirection/conversion to the E-mu 8000 I/O ports for the AWE32/64 E-mu 8000 based engine for the Win98 DOS mode, or it allowed direct MIDI I/O AWE32/64 game port pass-thru (buggy) to an external MIDI device.
If your sound-card is a Creative SB32/AWE32/AWE64 with the correct drivers and the AWE32 Control Panel applet then DOS mode MIDI I/O port re-direction is possible. Otherwise, you are dependent on another ISA sound-card's driver support for MIDI I/O port re-direction for the Win98 DOS 'emulation' mode. Of course, if your SC-8820 MIDI ports are truly hosed, then you are out of luck.