Modding Cartidges, Diagrams with Stereo & Clock Oscilator ...

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By Dhampird

Hero (584)

Dhampird's picture

05-10-2011, 05:08

Hello, here are some diagrams how i mod some important-essential cartidges, perhaps be helpful for any msx users... this mods works perfect in MSX2 HB-F9S and Turbo-R A1-GT, (in GT i get some background noise due to redirecting PSG (IN-OUT), but refereing to cartidges the mods work)

MEGAFLASHROM SCC+

img830.imageshack.us/img830/6803/megaflashromsccstereoou.jpg

img824.imageshack.us/img824/8403/megaflashromscc358mhzos.jpg

img194.imageshack.us/img194/8216/megaflashromsccclksigna.jpg

That MegaflashRom SCC+ mod also works for Konami Ultimate Collection Cartidge, both cartidges have same hardware. Now i´m trying to know if is possibe get internal PSG cartidge signal from any FPGA pin or not, to allow get internal cartidge PSG through jack stereo. The 25K Variable resistors need to be adjusted to any point where we can ear sound ok for PSG and SCC-I. Works perfect with Msx Super Turbo. About yellow circle in last image (back side of cartidge) is no important, should be purple, the only important part is cut CLK that show in component side.

MMC/SD SINFOX V2.2

img262.imageshack.us/img262/6627/mmcsinfoxfinal.jpg

img842.imageshack.us/img842/4144/mmcsinfoxfinal2.jpg

I didnt install a switch between PIN49, but you can install it if will be needed. Most important for me is use this cartidge with Turbo and now, after the install I have no problems with SCC sound when Turbo is ON.

KONAMI REAL SCC-I SNATCHER CARTIDGE

img833.imageshack.us/img833/1816/frontmv.jpg

img12.imageshack.us/img12/5300/backig.jpg

Like in Sinfox, this cartidge is fully compatible with Turbo after install Oscilator, no more problems with SCC-I sound in Turbo Mode. I´m looking a way to convert this cart into Megaflashrom. Also i instaled 2 extra 64K memories. That blue line in last picture means that points are conected in cartidge component side, is not a cable conection.

Like you can see the procedure to mod the carts is very similar, i hope this simple diagrams can help.

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By Dhampird

Hero (584)

Dhampird's picture

05-10-2011, 05:46

To know how redirect your internal Msx PSG, follow this procedure:

http://www.msx.org/forumtopic12978.html

This allow get PSG sound through stereo jack, but probably some MSX´s will need extra modifications to work ok with it. I tried that procedure with perfect results in a MSX2 HB-F9S, in Turbo-R A1-GT also works, but a tiny background noise effect appear when volume is quite high, or only high, this interference is constant, i´m trying to find solutions for this, maybe extra amplifier is needed or extra circuit to avoid that buzz interference in sound.

There is a method that allow get PSG from A1-GT engine ,but i dont want touch the engine for now in this machine, should be a way to clear the audio PSG signal without that noise, and if i´m right get the PSG from the engine makes lost sound in TV or monitor towards RGB conector, anyways this could fix installing 2 rca in scart conector, but for now i´m trying to search any way to filter the sound with normal procedure, anyone knows about this issue in A1-GT?

By Dantyr

Resident (51)

Dantyr's picture

06-10-2011, 04:36

Dhampird, Nice Job !

But as I'm little dumb on electronics, mind to answer some questions about the first photo (stereo mod) ?

- Where I use the 4K7 Resistor ?
- The 22uF Electrolitic capacitor is of what voltage ?
- What is the "4701" on the stereo jack ?

I'm thinking to do this mod on my cartridge because I have a problem hearing the SCC sound on my Sanyo 2+ (very low volume), so I think this stereo mod could be a good solution to solve this. What you think ?

Thanks,
Daniel

By Dhampird

Hero (584)

Dhampird's picture

06-10-2011, 05:41

Hello Dantyr, about:

- Where I use the 4K7 Resistor ?

-The 4K7 resistor is located in stereo jack, is draw like a rectangle, there you can see 4701, that is the SMD resistor 4K7 or 4701 ohm.

- The 22uF Electrolitic capacitor is of what voltage ?

-You can use smd 22uF 16V.

- What is the "4701" on the stereo jack ?

-Like i said, the "4701" is a smd resistor, when you get the smd type resistor you´ll see label on it 4701 in white (that is the reason why i drawed like is showed in diagrams)

I'm thinking to do this mod on my cartridge because I have a problem hearing the SCC sound on my Sanyo 2+ (very low volume), so I think this stereo mod could be a good solution to solve this. What you think ?

What kind of cartidge do you try to modify? Maybe you could use a 25K Variable resistor for test, to try recognise the desired sound value that you want to ear, after that, you could change that variable resistor for a normal resistor with same value tested for SCC sound, PSG is another thing, because you should need redirect internal MSX PSG signal to get PSG sound through stereo jack. I dont know about Sanyo 2+ hardware to try PSG internal redirect, maybe this will be interesting to you because you can get PSG+SCC sounds with stereo jack if you try that procedure, you can see above the link.

By Dantyr

Resident (51)

Dantyr's picture

06-10-2011, 14:00

Hi Dhampird! Thank you for the clear answer!

The cartridge that I will going to try is the MegaFlash SCC+, because it's the only one that I have mixing problems with my Sanyo. I also have an MMC/SD from Sinfox but the SCC sound is perfect.
Just another question, I will have to modify my MSX internally to grab the PSG sound on pin 49 of the slot ? If so, there is no way I can do it without messing up with the msx ? I was thinking to pick just SCC sound from the jack and the PSG from the normal audio output, it's that possible ?

Thanks,
Daniel

By OeiOeiVogeltje

Paragon (1229)

OeiOeiVogeltje's picture

06-10-2011, 17:00

yeah
first of all
very nice and clear pics of these modificaions!!

but i still have a question
what kind of stereo is this?
drums on one side and rest on other side?
or what?

By Dhampird

Hero (584)

Dhampird's picture

06-10-2011, 17:12

Hello Dantyr, if you want to mod the same Megaflahrom SCC+ then you should be able to use the same diagram that i used without problems. About PSG internal procedure, you can try it, i can tell that this PSG redirection is not a modification what be dangerous for the msx, but maybe, you will have to cut some tracks in your msx motherboard or remove some bridges to do right the PSG redirection, first of all you should get your Sanyo 2+ service manual datasheet , if it is available, and follow where cartidges pin49 goes into mobo, then you should compare that info after in your real msx to know if matches with service manual.

About pick just SCC from jack and after PSG from normal audio out, you can try, but i think that way you should need a device to mix SCC (get from stereo jack)+PSG (audio msx out) if you want ear that combination together, or joining that signals towards an external stereo jack (that works like stereo jack that i installed internally in cartidges) to can mix it, i´m not sure, but if through that audio output you talked, maybe you can ear now PSG and also SCC and not only PSG, if you can ear "only PSG" from that audio out in msx you´re talking about, maybe any kind of mix should possible, but i´m not sure about it. If you wish, try to make external mods first if you dont want touch msx inside, maybe you get good results that you can then post here like another point of view.

By Dantyr

Resident (51)

Dantyr's picture

06-10-2011, 18:31

Dhampird, thank you again for the new ideas.

I already bought some parts today in a local store and I will do part of your first schematic to just redirect SCC through an RCA female jack and the PSG would come through directly from the MSX audio out. As I use an X230 Logitech 2.1 speakers, the SCC will come in from one channel and the PSG in another channel. Would be two rca cables plugged (one on the cart and other on the MSX), but it's a small price to pay to not touch inside my MSX. As far as I know, no one never found schematics for the Sanyo 70FD.
I will also test the OPFX /P option to use the internal PSG on the Megaflash to see what will be the better combination.

After all the modifications I will take some photos to put on this topic if you don't mind.

Thanks,
Daniel

By ant0niutti

Master (159)

ant0niutti's picture

06-10-2011, 21:17

I know that SCC + cartridge !
\o/ Smile

By Wild_Penguin

Champion (500)

Wild_Penguin's picture

06-10-2011, 21:57

Hi!

Just asking, what is the point of the oscillator in a cartridge? Is there some problem with SCC if an MSX in installed with turbo, and this removes that problem?

By Dantyr

Resident (51)

Dantyr's picture

06-10-2011, 22:49

I know that SCC + cartridge !
\o/ Smile

I think that now I will solve this problem!

Tonight I will post the results..

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