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Roland SCC-1 - MIDI garbled?

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First post, by lazygamereviews

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So I recently grabbed an SCC-1, and on using the CHKSCC utility, I've run into an issue. The sound output is all garbled, and it's like I can only hear part of the drums and maybe a voice or two.

Does someone have an example of what the demo MIDI files are supposed to sound like? Or has anyone run into this issue? Everything looks physically fine on the card, and it detects it just fine. I'm using the headphones port for output. Does the same in Doom II as well...

Thanks!

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Reply 1 of 20, by bjt

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What's your machine?

IO address conflict with another card?
Some kind of weird ISA timing thing?

Reply 3 of 20, by lazygamereviews

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bjt wrote:

What's your machine?

IO address conflict with another card?
Some kind of weird ISA timing thing?

Pentium II 233Mhz, 32MB RAM, MS-DOS 6.22. Took out other card (an SB2.0), still the same problem. Not sure of the ISA timing or how to check/fix that? But I did try it in the other ISA port, same thing. Also changed the IRQ on the card, no luck.

keropi wrote:

any visual damage on the card ? a missing cap? dirt?

None that I can tell. Cleaned it, made sure everything was in place and not loose.

I've noticed that if I move my audio cable as it's plugged in the 3.5mm port, I get a bit more or less sound. Just barely though. Could be a bad port? And I can't seem to get any sound from the two RCA outputs.

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Reply 4 of 20, by bjt

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ISA timing controls might be in your BIOS, but if you're getting some output it's probably not that anyway.

Probably worth trying to clean the inside of the jacks with some isopropyl alcohol. They do oxidize over time.

I recently got another sound card which had garbled output on the line out. It turned out that one of the other jacks was bent inside so that one of the channels was shorted to ground when nothing was plugged into it. Bending the contact to prevent the short fixed it.

Reply 5 of 20, by keropi

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looks like it's port related ... but the fact that you don't get audio on the rcas is fishy... if you clean them and still get no audio then it means that there is a problem on the line-out circuit of the card

🎵 🎧 PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 6 of 20, by lazygamereviews

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So I cleaned and checked the jacks, all seems well with those. The RCA outputs work now, but I get the same garbled result. Also tried changing the I/O address, but to no avail. Plopped it in another machine to make sure it wasn't the ISA ports or anything, and nope, it sounds like the same messed up sound.

I've attached what E1M1 for Doom sounds like as an example.

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Reply 7 of 20, by sliderider

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Boy, I wish I had Roland SCC-1 problems. 🙁

Reply 9 of 20, by lazygamereviews

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Mau1wurf1977 wrote:

Can you test if the SCC-1 still works as a MPU401 interface for a MT-32?

I don't have an MT-32.

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Reply 11 of 20, by F2bnp

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keropi wrote:

It reminds me a capacitor problem, like the one we get on amigas after the sound caps start leaking or getting dry.

Exactly, this is the first thing that I thought too. Problem is, none of the capacitors look damaged or about to bulge, judging from the picture you uploaded. 🙁 Knowing where to begin could be an issue. Someone more experienced should add their 2 cents here.
Whatever the case, this sucks. I saw your photo on facebook, it really is a shame that you can't have fun with your SCC-1 Clint. Best of luck to you!

Reply 12 of 20, by keropi

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^ not always the case, caps could have leaked without bulging at all or visible damage except at the bottom where the leak is.

@lazygamereviews
C33 looks like it has leaked, what's that brown stuff next to it?
There is always the possibility that there was leakage at some point and someone cleaned it, so you have a dead cap that looks normal...
I would suggest a recap of the card, if you were in EU I'd do it for you for free...

🎵 🎧 PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 13 of 20, by F2bnp

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keropi wrote:

^ not always the case, caps could have leaked without bulging at all or visible damage except at the bottom where the leak is.

Of course! Perhaps I didn't phrase it right, I'm just saying it is kinda hard to know which one to begin with.

Reply 14 of 20, by lazygamereviews

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keropi wrote:

I would suggest a recap of the card, if you were in EU I'd do it for you for free...

Yes, now that you mention it there is a bit of brown that is suspicious. Crap. I'd love to have it recapped, just need to find someone skilled and with the time to do so, seeing as I have neither 😒
Am wanting to feature this on my show, but yeah, not going to be happening until I can fix the thing.

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Reply 15 of 20, by keropi

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Brown is the color of the dreaded cap acid... you can pour some vinegar or lemnon juice on the area (yes, vinegar) as they will neutralize any acid that is currently "working" on the card.
If you don't find a local repairman I'll be more than happy to recap your card as I stated before 😀

🎵 🎧 PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 16 of 20, by keropi

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allright, bringing the thread back from the dead since today I recapped lazygamereviews's SCC-1:

Cimg1926_zps68819be8.jpg

Sadly this did not fix the problem, it remains exactly the same.
I see on the card there is a NEC D6376 (AUDIO 2-CHANNEL 16-BIT D/A CONVERTER) and 2x 5218A (DUAL LOW-NOISE OPERATIONAL AMPLIFIERS - DUAL POWER SUPPLY TYPE) ICs. I am thinking of replacing them, first the D/A converter (since both channels are screwed) and then the 5218As ... I can't detect any damaged traces on the nearby area and the D/A converter is feeded from the large Roland R15239148 IC through FL2/FL3/FL4 .

On the bright side the MPU401 part of the card is fine and working perfectly 😀

Any recommendations/tips/ideas are highly welcomed! TIA! 😊

🎵 🎧 PCMIDI MPU , OrpheusII , Action Rewind , Megacard and 🎶GoldLib soundcard website

Reply 17 of 20, by ReeseRiverson

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Are these cards prone to problems or something?

Also good luck with trying to fix LGR's card. He definitely needs one of these going. 😁

Reply 18 of 20, by CkRtech

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keropi wrote:

I see on the card there is a NEC D6376 (AUDIO 2-CHANNEL 16-BIT D/A CONVERTER) and 2x 5218A (DUAL LOW-NOISE OPERATIONAL AMPLIFIERS - DUAL POWER SUPPLY TYPE) ICs. I am thinking of replacing them, first the D/A converter (since both channels are screwed) and then the 5218As ... I can't detect any damaged traces on the nearby area and the D/A converter is feeded from the large Roland R15239148 IC through FL2/FL3/FL4 .

keropi - did you ever end up replacing additional components on this card?

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