[Report] Konami SCC (standalone) with SofaRun

Resident (43)

28-08-2021, 17:14

Hi folks,

I recently managed to get a specific setup working on my MSX : SD cartridge for ROM games in one slot, Konami SCC in the other.
The target is to have music on Konami games which originally embedded a SCC chip, such as Parodius (sound is poor without chip, because so many channels are missing).

(If you already own a SD cartridge with SCC embedded (Carnivore 2, GR8NET, MegaFlashROM SCC+ SD), this is obviously unneeded for you. SofaRUN will make sure it gets used in SCC games !)

So here are the steps :

1) Grab an original SCC game cartridge.
Here are the ones which will work with these steps : Parodius, Pennant Race 1 & 2, F1-Spirit & A1-Spirit, Nemesis 2, King's Valley 2, Salamander.

I personally used Pennant Race, as I don't play baseball :

2) (OPTIONAL, BUT BETTER FOR TESTS) Open the cartridge.

Remove the front sticker. Use a flat & thin screwdriver to:
- GENTLY slide in the bottom of the 2 front holes (these ones break easily !), and push their ticks bottom-to-up, while using your hand to check when the corresponding side gets loose -so you know when to stop pushing;
- once the bottom part is loose and the side is half-opened, slide the screwdriver in the 2 now-visible side holes, with STRONG lever effect ;
- just open the cart with your hands, bottom-to-up.

3) Put cello tape on Pin 25,
which happens to be the 13th pin from the left on this picture :

(just in case: the underneath PIN must stay untouched, don't put cello tape on this one)

It will prevent the MSX to detect and run the game at boot time. Technically, you could insert the cart at runtime, which has a 25% chance of frying your MSX ;) ... hence the "mod"!

4) Insert the "modded" SCC in the 2nd slot :

(I'm using a SD-512 on this photo, this one actually doesn't work due to a side problem -feel free to report on other SD carts!)

5) Now use SofaRun,
to run a compatible .DSK/.ROM (Parodius is a good one). Go to "Settings" -> "External SCC: Yes".
Autodetection should work, otherwise you can use the "SCC slot" setting (Slot 2 is the front one on my NMS 8220).

(you need a recent SofaRun; I needed to upgrade 4.1->8.0 because it didn't work initially)

SofaRun will patch the game at runtime to redirect the calls, and here you go!

(thanks to @Louthrax and BiFi's tutorial for their help)

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By sdsnatcher73

Enlighted (4289)

28-08-2021, 18:20

Good job, it is a nice feature of SofaRun indeed!

By Tarnyko

Resident (43)

29-08-2021, 13:28

Seems like the pictures don't always appear on the forum (probably for performance reasons), so here are the links :

- Pennant Race game box
- Opened SCC (Pennant Race) cartridge
- Cello tape on 13th pin
- Catridges final setup
- SofaRun configuration

By mars2000you

Enlighted (6556)

29-08-2021, 13:38

Tarnyko wrote:

Seems like the pictures don't always appear on the forum (probably for performance reasons), so here are the links :

- Pennant Race game box
- Opened SCC (Pennant Race) cartridge
- Cello tape on 13th pin
- Catridges final setup
- SofaRun configuration

Because it's http links, not https links. Security measure in Google Chrome and probably other browsers based on Chromium.

By gdx

Enlighted (6429)

29-08-2021, 14:05

This cartridge would have avoided damaging your cartridge:

https://www.msx.org/wiki/Popolon_Sound_Cartridge

Its price is probably equivalent to what you could have gotten by selling your Pennant Race cartridge, and you can do more with it.

By Tarnyko

Resident (43)

29-08-2021, 16:48

Hi gdx,
I knew about Popolon SC, but there was none available back then, so I ordered Pennant Race instead (whose box I also plan to re-use for another project).

By gdx

Enlighted (6429)

29-08-2021, 17:33

I think these cartridges are still available from time to time in very small quantities. You have to wait or contact directly Popolon.

About your modification, I think it's not a good thing to leave a chip's address pin unconnected. It can potentially do damage, and the tape can make the contact worse because of the added thickness (among others). A pull-up resistor (that can be controlled by a switch) is preferable.

By Tarnyko

Resident (43)

29-08-2021, 20:53

Hmmm, you may be right. I dismissed the resistor/switch thing because it seemed overkill, but I may want to do it -even if just for fun. Let's stay in touch.

By Wild_Penguin

Hero (644)

30-08-2021, 10:22

Also, I don't think it is really necessary to open the cartridge just to put the tape on the pin (*). It is quite easy to do without opening - just use some sharp-pointed tweezers, or even a flat-headed screwdriver. Really, not needing to open the cartridge is the only sensible reason to use the tape trick IMHO....

However, I also agree with gdx though, it is not a good idea to have a pin floating, especially for prolonged times (for short tests the risk is quite small, probably...).

But there are so many new SCC+ (albeit FPGA implementation) carts for sale, and accounting for the rise of appreciation and price of the original carts, at their price range. So one might want to think twice before opening up a cartridge or using the tape trick (and risking damage to the cartridge sticker, case or ROM chip!). But YYMV - if one has an original SCC game floating around, and no re-implementation (and only little money), then, well... everyone makes their own decision!

*) OTOH, if one goes trough the trouble of opening up a cartridge, then why not put a switch - or a jumper header - and the appropriate pull-up resistors? Or a switch inside their MSX (better option than potentially damaging a cartridge)? For the former mod, a small switch or a jumper header enables to not damage the cartridge, as it fits inside, but of course, that will make toggling the switch difficult. But one already has some kind of flash cartridge if one goes trough the trouble of making this mod, so the need to toggle the switch will be quite seldom (but it is still a good thing to have in case one needs to revert or redo the mod)...

EDIT: Added links. Oops edited the sentences also in the process of doing that ;-)

By gdx

Enlighted (6429)

30-08-2021, 15:45

Use a tape the lesser thick as possible. About the unconnected pin, the problem doesn't occur on all types of chip. So maybe everything will be without problem.