CX5M Upgrade from SFG-01 to SFG-05 help!

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By gwpt

Supporter (2)

gwpt's picture

06-07-2009, 06:01

Hi,
I am trying to upgrade my CX5M from SFG-01 to SFG-05...

I have found some info on the web, but nothing complete...
From what I can gather... one has to:

* Upgrade the ROM from the 16k to the 32k one (I have found a rom image)
* Run a wire to get the a14 address line working, from the EPROM to the Cartridge port

From the following web search:

" Hi all. I've done another little hardware modification, this time
upgrading the ROM of a Yamaha SFG-01 FM Sound Synthesizer Unit to that of
a Yamaha SFG-05 FM Sound Synthesizer Unit II. This was a little more
complicated than simply exchanging the ROMs, since the SFG-01 uses a 16K
ROM and the SFG-05 uses a 32K ROM. Address line A14 from the cartridge
connector is soldered to A14 on the EPROM. "

Has any body got a copy of the jpg??
ie: http://student.cusu.cam.ac.uk/~rga24/pics/msx/sfg-01-05.jpg

* and then, replace the FM chip for the 'new' YM2164

Does anybody know if this last step is actually needed?

Can I just upgrade the ROM and be able to drive the CX5M from an external midi source?
Thanks! :)
G

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By Sander

Ambassador (1845)

Sander's picture

08-07-2009, 13:23

Quote:

"* To upgrade the SFG-01 cartridge to a SFG-05 you have to connect address line A14 from the EPROM (IC104, replace with type 27C256). Solder a wire between pin 27 of the new EPROM to pin 35 of the side slot connector. Remove the 5V connection on the circuit board between pin 27 and 28 on the EPROM. (Thanks to Erwin Meeder for the 5V Addition.)"

from www.cx5m.net (everything you need)

By gwpt

Supporter (2)

gwpt's picture

15-07-2009, 13:01

Thanks Sander for the reply....

but...

Ive done everything said above but all it not well Sad

When I turn the CX5M on, it's ok. but when I type 'CALL MUSIC'
The screen just goes white and the machine freezes. (I have verify the EPROM image is correct)

Has anyone seen this behaviour?

Thanks
Guy

By Dirk01

Supporter (3)

Dirk01's picture

25-11-2010, 19:23

Hello,
my upgraded SFG01 with SFG05 Eprom has lost its preset tunes with the new eprom.
The software starts with call music and keypresses are recognized.
With SFG01 Eprom all is o.k
Could it be that some SFG01 units incompatible with the new SFG05 bios ?

By teevee

Supporter (5)

teevee's picture

10-04-2018, 21:26

Sander wrote:

Quote:

"* To upgrade the SFG-01 cartridge to a SFG-05 you have to connect address line A14 from the EPROM (IC104, replace with type 27C256). Solder a wire between pin 27 of the new EPROM to pin 35 of the side slot connector. Remove the 5V connection on the circuit board between pin 27 and 28 on the EPROM. (Thanks to Erwin Meeder for the 5V Addition.)"

from www.cx5m.net (everything you need)

The last part with removing the 5v connection on the PCB board, how do you do that? :)

By Grauw

Ascended (8516)

Grauw's picture

10-04-2018, 21:39

Hi teevee, if it was you that contacted me by email, I can’t respond because for some reason your provider is blocking my email. However I haven’t got details about how to upgrade the SFG01, mine was upgraded when I bought it.

By Alexey

Guardian (2459)

Alexey's picture

11-04-2018, 00:35

teevee wrote:

The last part with removing the 5v connection on the PCB board, how do you do that? Smile

No need to mess with the board. Just bend the pin upwards and solder a wire to it to connect to slot's A14 signal:

And of course you need the patched SFG-05 BIOS, otherwise this won't work.

By teevee

Supporter (5)

teevee's picture

11-04-2018, 07:36

Alexey wrote:
teevee wrote:

The last part with removing the 5v connection on the PCB board, how do you do that? Smile

No need to mess with the board. Just bend the pin upwards and solder a wire to it to connect to slot's A14 signal:

And of course you need the patched SFG-05 BIOS, otherwise this won't work.

Hello Alexey,
thank you for the picture above. Do you have a picture of the backside too? (I tried searching “google”, but was not able to find one)?

Concerning the software. I have found the two following roms:
1. http://www.cx5m.net/software/
2. https://www.msx.org/forum/msx-talk/hardware/yamaha-sfg-05-cx... < from Grauw

I tried making a checksum test on both roms and came to the conclusion, that they are not the same. The rom OS from CX5m.net is the one, which is not patched and requires an additional modification with removing a 5v trace on the PCB board, while the rom from Grauw only requires the connection between two spots, correct?

The last two users (gwpt & Dirk01) here on the topic who tried to perform the modification about 8 years ago, were unsuccessful. I was therefore wondering because the required steps are not really complicated.
1. Burn eprom chip.
2. Make connection a short connection on two spots on the backside of the PCB board.
3. Remove the 5v trace on the PCB board (if you use the revision provided from CX5m.net)

Last question:
Is it necessary to change the FM synthesis sound chip to another model or is this patched correctly too?

TeeVee

By Grauw

Ascended (8516)

Grauw's picture

11-04-2018, 08:29

The SFG-05 ROM needs an YM2164 OPP. But my ROM works with the YM2151 OPM, it's been patched for it (that's the reason I dumped it).

By Alexey

Guardian (2459)

Alexey's picture

11-04-2018, 10:19

Only one wire needed for this upgrade. I will try to find a picture for you. Bending the pin upwards helps to preserve the board in case you want to go back to SFG-01. On my picture the second EPROM chip has the original 01 BIOS.

And don't bother to desolder the old EPROM - just cut the pins close to the chip's body and then pull the cut pins gently out while applying heat on them from the other side of the board.

By teevee

Supporter (5)

teevee's picture

11-04-2018, 13:52

Grauw wrote:

The SFG-05 ROM needs an YM2164 OPP. But my ROM works with the YM2151 OPM, it's been patched for it (that's the reason I dumped it).

Thank you for sharing the rom dump and great that changing the Yamaha sound chip is not necessary, because tracking down those sound chips can be a challenge nowadays.

Alexey wrote:

Only one wire needed for this upgrade. I will try to find a picture for you. Bending the pin upwards helps to preserve the board in case you want to go back to SFG-01. On my picture the second EPROM chip has the original 01 BIOS.

And don't bother to desolder the old EPROM - just cut the pins close to the chip's body and then pull the cut pins gently out while applying heat on them from the other side of the board.

I would appreciate, if you are able to find or provide a picture of the SFG-01 PCB boards’ backside. (Even more, if the SFG-01 have been modified to SFG-05 for the documentation)

What are the benefits/reasons to downgrade back from modified SFG-05 -> SFG-01?

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