I did some measures and something does come out from the MIDI port of the computer through the cable, which behaves as a signal and only appears if the output is the MIDI port and I play something.
So the cable is not confirmedly good, but not totally wrong either.

I dug up my Win98SE machine with SB16 and no luck, neither in DOS mode. SC-55 simply does not respond to anything plugged into the midi ports.

I have not used my SC-55 (or any other ext. MIDI device) under Windows 9x so far, but normally, you go to the MIDI Mapper and select "MPU-401" and keep using i/o port 330. When using the AWE64, you may have to do this using the AWE control panel.

Besides, the SC-55 has a demo song which you can just play in order to see if the unit is working correctly.

The demo songs work correctly.
I am using MPU-401 emulation and have tried port 330 and 300 too. As I measured with a multimeter the MIDI signal goes out on the gameport cable.
Either I am missing some detail or there is some hardware defect here...

Silly question: is the selector switch on the back of the SC-55 set to "MIDI" and not PC/Mac/whatever?

Yes yes, it is on MIDI, though I have tried all positions now...

Sorry, I don't have any other suggestions. Your post covered anything else I might suggest. Unless you had any other Midi equipment (Keyboard, MT-32, whatever). If you do, I'd suggest trying that instead to isolate the computer half from the SC55 half.

Sadly I don't have any of these, SC-55 would be my first one. I will try to ask for help locally.
I actually went cheap on the gameport MIDI cable and picked one locally for about 3 EUR from a musician who bought it back in the days and never used it. It might be wrong, though when I measured the out with a multimeter it seemed to be okay.
I just found the eBay prices really high for a gameport cable and no one else sells them anymore. But we will see what the root of the issue is, I have to figure it out...

The SC-55 MKII is in mint condition, bought from Yappari-Japan eshop, so I doubt it would be defected.

Check out this thread from 2013. It may just get you going.

AWE32 / AWE64 : Use external midi in Windows 95 dos session

Hmm, thanks for the reply, strange stuff.
I have tried out playing a .mid in Windows Media Player and I could measure the output with a multimeter on the gameport. (on the 5-PIN DIN to be more specific). I can also measure signal when I play Duke3D in a Win98SE or WinME DOS box. I believe my card does output on gameport but yeah, I think I should make some vanilla 6.22 testing.
Haven't tried disable MPU-401 yet.

Since you didn't mention anything about configuring the SC-55 front panel, I'll just add here to reset the thing to factory defaults before using it: Power on while pressing both Instrument arrows and confirm with All. (Or even just completely remove the internal battery that holds settings when powered off.)

The manual could be handy: http://cdn.roland.com/assets/media/pdf/SC-55MKII_OM.pdf
Page 79 looks like something to check out, for one.

It has been resetted and initialised before testing.
I will take it to an MT-32 owner this weekend, and we will test.

Have you tried the front MIDI input port on the SC-55?

I did see one thread where the person found out that the power and data lines were somehow switched in the cable they had. That could also be a possibility.

Front port has been teste ofc. I no longer plan or have time to investigate without a reference device. Hopefully this weekend I will know what's the root of the issue.

Well, the guy who helped me couldn't make Gameport MIDI work either. Not in his entire retro gaming history. But he has an original MPU-401 and a USB MIDI adapter. SC-55 worked fine with both of them.
I already ordered an USB MIDI, about MPU-401 or trying with softMPU, I don't know yet.

Has gameport midi just worked for anyone? If yes, then on what OS and what card, which settings?

I think that you'll see that a lot of people did get gameport MIDI to work on this forum. It's likely the most used method (besides dedicated MIDI interface cards). The other method you could try is installing the Roland serial-to-MIDI driver and use a serial cable to connect the SC-55. If MIDI works that way (and it should), either your AWE64 is misconfigured or your gameport-to-MIDI cable is not soldered correctly.

Yeah, I have seen that this is a common way and should just work out of the box. I have the exact same model of gameport cable as the one, who helped me, so we couldn't test different cable models (we tested his cable though).
I was thinking about getting the serial cable, it was one of the main reasons I choose the MKII, but I don't have a cable yet.
Next think I will try I guess is playing a *.mid on Windows XP and using the onboard gameport of a Pentium 4. I have seen the dreamblaster adapter on eBay advertised with this.

Yesterday we also tried several SoundBlasters in my PC with DOS6.22 from CF-IDE, and none of them could output MIDI... Not even with softMPU+DOOMII. Whereas MPU-401 just worked fine.

quailstorm wrote:

Yeah, I have seen that this is a common way and should just work out of the box. I have the exact same model of gameport cable as the one, who helped me, so we couldn't test different cable models (we tested his cable though).
I was thinking about getting the serial cable, it was one of the main reasons I choose the MKII, but I don't have a cable yet.

IIRC, the SC-55 manual shows how to wire your own cable (it's in the back of the manual).

Next think I will try I guess is playing a *.mid on Windows XP and using the onboard gameport of a Pentium 4. I have seen the dreamblaster adapter on eBay advertised with this.

If it works. My Windows XP SP3 installation and drivers don't see my Creative AudioPCI MIDI features... Be sure to select the right output port in your system settings (note: this means changing the MIDI playback device).

Yesterday we also tried several SoundBlasters in my PC with DOS6.22 from CF-IDE, and none of them could output MIDI... Not even with softMPU+DOOMII. Whereas MPU-401 just worked fine.

The Soundblasters didn't even work when explicitly selecting for MPU-401 output in DOS games supporting MIDI music? If multiple sound cards don't work, that basically leaves two options: user error or hardware issue beyond the sound cards. What kind of system (motherboard etc., but also OS) are you using?

quailstorm wrote:

Has gameport midi just worked for anyone? If yes, then on what OS and what card, which settings?

I have successfully used the gameport midi output from my AWE64 gold. It has worked with and without softMPU depending on the game I was playing.