Forums

Sega Master System / Mark III / Game Gear
SG-1000 / SC-3000 / SF-7000 / OMV
Home - Forums - Games - Scans - Maps - Cheats - Credits
Music - Videos - Development - Hacks - Translations - Homebrew

View topic - Writing ROMs to EPROM

Reply to topic
Author Message
  • Joined: 22 Feb 2020
  • Posts: 49
  • Location: Washington, DC
Reply with quote
Writing ROMs to EPROM
Post Posted: Sat Dec 19, 2020 12:08 am
I'm kind of a purist and like playing games from a cart on actual hardware.
I want to play the Phantasy Star retranslation on my J-SMS to enjoy the FM sound and while an Everydrive would be the easiest solution, I want something a little more unique.

I'm looking to write the Phantasy Star retranslation to an EPROM and solder it either into a donor J-SMS cart or an export SMS cart (I have an adapter). I'm not sure I want to buy a writer just for a one-off, but I found someone who has one and will write whatever ROM you give them onto an EPROM. The thing is, I'm not sure which one to pick.

Their site is: https://mattsbasementarcade.com/product/custom-rom-eprom-programming/ and there are a slew of chips in the drop-down.

Id honestly prefer not to have a UV erasable one, but I can deal with it if its my only option. I'm going for that vintage look (even on the internals).

Can anyone here point me in the right direction or give suggestions?
  View user's profile Send private message
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 13692
  • Location: London
Reply with quote
Post Posted: Sat Dec 19, 2020 1:48 am
Vintage EPROMS have little white paper stickers over the window to stop accidental erasure...

I think it is somewhat dependent on your donor cartridge. Can you narrow that down and open it up?
  View user's profile Send private message Visit poster's website
  • Joined: 22 Feb 2020
  • Posts: 49
  • Location: Washington, DC
Reply with quote
Post Posted: Sat Dec 19, 2020 3:27 am
I'll either use a US Phantasy Star (probably not my childhood one, id buy a "donor"). I have a Phantasy Star coming from Japan, but it hasn't gotten here yet.

My US one pic is below... I recently swapped out the battery and kept my saves from 30yrs ago

  View user's profile Send private message
  • Site Admin
  • Joined: 19 Oct 1999
  • Posts: 13692
  • Location: London
Reply with quote
Post Posted: Sat Dec 19, 2020 9:16 pm
I did some digging... https://www.smspower.org/forums/1615-ROMPinout gives a pinout for the Sega ROM and that seems to me to be a perfect match to what I see for 27C040 online. (The discussion about the Am29F040B needing some rewiring is only where it differs from the 27C040.)
  View user's profile Send private message Visit poster's website
  • Joined: 22 Feb 2020
  • Posts: 49
  • Location: Washington, DC
Reply with quote
Post Posted: Sun Dec 20, 2020 4:47 pm
Thanks! Now I just need to find a donor cart. (Dont want to use my childhood one). I cant believe the carts (even without box/manual) are so expensive.

I have 2 J-SMS carts coming from a friend in Japan, those combined cost less than 1 US cart. I'm going to keep one as is and open the other up. If at all possible, I'd just swap the chip into it. That was my original plan about a year ago.

I think the better way would be to us an export cart because they have wider compatibility, I'll play it by ear.
  View user's profile Send private message
  • Joined: 22 Feb 2020
  • Posts: 49
  • Location: Washington, DC
Reply with quote
Post Posted: Mon Jan 04, 2021 10:19 pm
I dont have any extra Export SMS Phantasy Stars, but I did order 2 Japanese Phantasy Stars (much cheaper!) that arrived today.

I took one apart using a heat gun to gently peel back the label. Do you think I could use the same chip on this board or are the EPROMs different? It looks like they use the same mapper (315-5235), but I must admit, I'm a bit out of my element



  View user's profile Send private message
  • Joined: 13 Jul 2018
  • Posts: 10
Reply with quote
Post Posted: Sat Jan 23, 2021 11:04 pm
Last edited by Asisluque on Sun Jan 24, 2021 12:53 am; edited 1 time in total
Hi
Are you still interested? I have done it before a few times, always using old cartridges. That is
- supper tennis chip can easy be by replaced with 32kB EEPROM
- after burner can used for up to 512kB games.

I bought a TL866II programmer in AliExpress (30€ approx) and I replaced chips to get Out Run 3D, Woody Pop, Silver Valley and 3D gunner games in cartridges. My next one will be Smurpfs 2. Yes I now, original is better, but too expensive...
  View user's profile Send private message
  • Joined: 13 Jul 2018
  • Posts: 10
Reply with quote
Post Posted: Sat Jan 23, 2021 11:33 pm
PS: for your jap-PCB and chip (in order to keep battery functionality) it could be necessary to identify the pinout of all chips. I see there the same Mapper chip used in After burner: 315-5235. So, the EEPROM should be typical one used for replacing it: AT27C40.

  View user's profile Send private message
  • Joined: 22 Feb 2020
  • Posts: 49
  • Location: Washington, DC
Reply with quote
Post Posted: Wed Mar 17, 2021 11:35 pm
Asisluque wrote
PS: for your jap-PCB and chip (in order to keep battery functionality) it could be necessary to identify the pinout of all chips. I see there the same Mapper chip used in After burner: 315-5235. So, the EEPROM should be typical one used for replacing it: AT27C40.


Hello, yes, I'm still interested. Life has been sidetracking me, but I want to do this. I want to get the SMSPower Phantasy Star ROM written to an EPROM so I can put it in the Japanese Cart and use it on a Japanese SMS.

My goal is to play (as close to) the original game in English as possible. Original hardware, original chips (except the eprom of course). Electrical Engineering/Computer Science are not my specialty. I can do the manual stuff like solder, but want to be absolutely sure I'm buying the right EPROM. I only plan on doing this once, or I'd buy an EPROM writer myself.

The easy way is to get an Everdrive, but I want to go the hard way with Phantasy Star. I still have a task of going through the translated manual and checking the grammar, too
  View user's profile Send private message
  • Joined: 13 Jul 2018
  • Posts: 10
Reply with quote
Post Posted: Sun Mar 28, 2021 11:00 pm
Tha_Ape wrote

Hello, yes, I'm still interested. Life has been sidetracking me, but I want to do this. I want to get the SMSPower Phantasy Star ROM written to an EPROM so I can put it in the Japanese Cart and use it on a Japanese SMS.

My goal is to play (as close to) the original game in English as possible. Original hardware, original chips (except the eprom of course). Electrical Engineering/Computer Science are not my specialty. I can do the manual stuff like solder, but want to be absolutely sure I'm buying the right EPROM. I only plan on doing this once, or I'd buy an EPROM writer myself.

The easy way is to get an Everdrive, but I want to go the hard way with Phantasy Star. I still have a task of going through the translated manual and checking the grammar, too


Ok. The key is to identify each pin of the MPR-11198 chip. If you are able to follow the track for each one and tell me with which pin from the other chip is joined each one of this one, I can check if it can be replaced by an standard EEPROM and the eventually changes to be made in the PCB -maybe one cut and one soldering but no much more.
  View user's profile Send private message
Reply to topic



Back to the top of this page

Back to SMS Power!