Making SEGA Genesis cartridges

[pbj]

thats hilarious, i do the opposite... i use my game genie to plug in curved SFC games to my square ass console. i could mod it to take them, but i'm lazy

It's literally snapping off two pegs on the inside of the cart slot.  I believe in you. 

My rational was $30 for Super Famicom, or $65 for SNES.  SNES Game Genie was bought in a ~$15 lot with the Genesis one I actually wanted.  I honestly didn't even know if it worked until yesterday.  Super Famicom uses a stupid center negative power supply, but it's a common plug size.  I just cracked open a 9V 1A power supply from the junk pile and reversed the polarity.  Already had the AV cable and controllers.  I don't know if it's awesome or sad that I have all the accessories for 30 year old consoles laying around and can buy loose consoles and be fine... but here I am.

Thanks for the help, Yeah I believe it to be easier to just get the right ones. Do you have a suggestion on where to buy or is ebay the best option?

Well, how many is a "ton?"  It might be fun to program a chip and run a bunch of jumper wires.... once.

I get my EPROMs off AliExpress.  Last order was ~$35 shipped for 50 x 2MB (27C160) that I received last week.  It's been a total crap shoot with the quality.  Latest batch was actually shipped in antistatic sleeves of 5 chips and they're very clean.  I've burned 2 and they're fine so far.  I've had other batches where they've been thrown haphazardly into a bubble mailer.  Others have been stacks of ten neatly shrink wrapped.  The poorly shipped batch was actually mostly fine once I patiently straightened the legs.  One of the nice looking batches was about 30% useless.  Just embrace that all of this is a waste of money.  Don't bother with buying smaller than 2MB EPROMs because it's just a matter of pulling 2 pins high if you're using a 40 pin PCB and they're all the same price.


 

[bulldawg]

I have a couple hundred probably. Yeah its a waste of money because i have a mega everdrive pro. But I like tinkering with stuff especially modding consoles and soldering etc. Keeps my soldering skills up to date. lol

[bobbyb13]

What's not to love about nostalgia hoarding that pays off?! 
If I didn't have a workshop 100 meters from the house to hide ---steaming pile of meadow muffin--- in I would probably get kicked out by the missus.

thats hilarious, i do the opposite... i use my game genie to plug in curved SFC games to my square ass console. i could mod it to take them, but i'm lazy

It's literally snapping off two pegs on the inside of the cart slot.  I believe in you. 

My rational was $30 for Super Famicom, or $65 for SNES.  SNES Game Genie was bought in a ~$15 lot with the Genesis one I actually wanted.  I honestly didn't even know if it worked until yesterday.  Super Famicom uses a stupid center negative power supply, but it's a common plug size.  I just cracked open a 9V 1A power supply from the junk pile and reversed the polarity.  Already had the AV cable and controllers.  I don't know if it's awesome or sad that I have all the accessories for 30 year old consoles laying around and can buy loose consoles and be fine... but here I am.

Thanks for the help, Yeah I believe it to be easier to just get the right ones. Do you have a suggestion on where to buy or is ebay the best option?

Well, how many is a "ton?"  It might be fun to program a chip and run a bunch of jumper wires.... once.

I get my EPROMs off AliExpress.  Last order was ~$35 shipped for 50 x 2MB (27C160) that I received last week.  It's been a total crap shoot with the quality.  Latest batch was actually shipped in antistatic sleeves of 5 chips and they're very clean.  I've burned 2 and they're fine so far.  I've had other batches where they've been thrown haphazardly into a bubble mailer.  Others have been stacks of ten neatly shrink wrapped.  The poorly shipped batch was actually mostly fine once I patiently straightened the legs.  One of the nice looking batches was about 30% useless.  Just embrace that all of this is a waste of money.  Don't bother with buying smaller than 2MB EPROMs because it's just a matter of pulling 2 pins high if you're using a 40 pin PCB and they're all the same price.


 

[bulldawg]

I considered a pi and a Kade and chose otherwise.  We are into retro gaming because it is expensive and inconvenient.

 

Could you highlight the areas you had to cut on the back? Or let me know if the circled areas I have are correct. Im trying this with madden 93 and just want to make sure im cutting the correct places?

[pbj]

Your circles look correct.  I really, really suggest you try desoldering the Madden ROM before you spend too much time on that PCB.  It was taking me literally hours to pull parts off of them versus entirely stripping a SEGA PCB within 5 minutes.  If you come up with a quicker method for the EA boards, I would love to hear it.

 

[bulldawg]

I already got the chip removed and installed a socket. Verified it still works with original chip (madden 93). I ending buying about 10 ea sports games because they were cheap. Took me about 30 mins. to desolder original chip and install socket. I used this desoldering iron in the pic and go through all the pins and the pins that didn't come clean the first go round (about 6 pins) I resoldered them with flux and got them clean the second time.

[bulldawg]

Actually I was wrong I haven't opened madden 93 yet, It was nhl 93 and its 40 pins. The board layout looked the same at first glance. Now have to figure out how to mod this pcb.

[Mike A]

Now there are two of you.

I love it.

Keep posting.

[pbj]

Actually I was wrong I haven't opened madden 93 yet, It was nhl 93 and its 40 pins. The board layout looked the same at first glance. Now have to figure out how to mod this pcb.

I'm curious.  Are you in a 220V country?  I've looked at that type of iron and heard they don't work as well on 110V.  Should have just gone ahead and bought one, would have saved me a ton of time apparently.  I think I've mentioned previously that there was one era of EA cartridges manufactured in Puerto Rico that had really soft solder.  So soft you can just pull the chips off with a flathead screwdriver.  Other people have told me that they have no problem whatever with EA cartridges, so I'm still not sure what to make of it.  I can desolder SEGA PCBs so cleanly that the chips fall off with gravity.

 

For the 40 pin PCBs, just burn a 512Kb game, bend up legs 1 and 42, and then tie those two legs to 5V.  I don't recommend running jumper wires to the cartridge edge connector.  I did it and screwed up my female connector on my Genesis motherboard.  That was before I was using Kynar wire, though.

Anyway, Malenko and I have made an enormous library of Genesis cartridge labels suitable for printing.  It's his google drive so his call if he wants to post it publicly.

 

[Malenko]

Anyway, Malenko and I (mostly Malenko) have made an enormous library of Genesis cartridge labels suitable for printing.  It's his google drive so his call if he wants to post it publicly.

FTFY
https://drive.google.com/drive/folders/1tVZb-Crq0XpU-4xo4HXjcYyn5VgqTLa-?usp=sharing

they arent perfect, some are super custom.

[bulldawg]

Actually I was wrong I haven't opened madden 93 yet, It was nhl 93 and its 40 pins. The board layout looked the same at first glance. Now have to figure out how to mod this pcb.

I'm curious.  Are you in a 220V country?  I've looked at that type of iron and heard they don't work as well on 110V.  Should have just gone ahead and bought one, would have saved me a ton of time apparently.  I think I've mentioned previously that there was one era of EA cartridges manufactured in Puerto Rico that had really soft solder.  So soft you can just pull the chips off with a flathead screwdriver.  Other people have told me that they have no problem whatever with EA cartridges, so I'm still not sure what to make of it.  I can desolder SEGA PCBs so cleanly that the chips fall off with gravity.

 

For the 40 pin PCBs, just burn a 512Kb game, bend up legs 1 and 42, and then tie those two legs to 5V.  I don't recommend running jumper wires to the cartridge edge connector.  I did it and screwed up my female connector on my Genesis motherboard.  That was before I was using Kynar wire, though.

Anyway, Malenko and I have made an enormous library of Genesis cartridge labels suitable for printing.  It's his google drive so his call if he wants to post it publicly.

 

Im in the US, so 110v. I actually have a 40 pin m27c4002 eprom burned and it does not work. Don't know if its the chip or if I need to mod the pcb. Figured with them being 40 pins and same size it would work without mods but no. I burned the the same image to a 42 pin 2mb rom and put in a 42 pin 2mb cart and it works. All the ones I've desoldered so far are assembled in the usa.

[bulldawg]

Anyway, Malenko and I (mostly Malenko) have made an enormous library of Genesis cartridge labels suitable for printing.  It's his google drive so his call if he wants to post it publicly.

FTFY
https://drive.google.com/drive/folders/1tVZb-Crq0XpU-4xo4HXjcYyn5VgqTLa-?usp=sharing

they arent perfect, some are super custom.

Thanks for sharing.

[pbj]

Did you swap the bytes?

https://www.romhacking.net/utilities/1621/

Also check the unswapped rom in Kega Fusion first and make sure you don’t get error messages.

[bulldawg]

Lighter fluid is $1.50 here for a 32oz bottle.  I have 4oz in that plastic food tub and so far I’ve removed six labels.  Put the lid back on and it doesn’t evaporate.  I’m good.

Labels are printed on a color laser on full sheet mailing labels.  I can get six per sheet and have enough room to make EPROM labels.  The sheets are 10 cents each.

Here’s a 42 pin 2MB eprom running a half megabyte game on a 40 pin pcb.  Legs 1 and 42 are bent up and tied to ground.  Works perfectly.

 

How to get a 42 pin 2MB eprom running on a 512mb 42 pin pcb?

[bulldawg]

Did you swap the bytes?

https://www.romhacking.net/utilities/1621/

Also check the unswapped rom in Kega Fusion first and make sure you don’t get error messages.

Yep byte swap and checked in kega.

[pbj]

What rom are you trying to run?  If it’s 512Kb, you bend up eprom pins 1 and 42 and jump them to 5V.  If it’s 1MB or 2MB, follow my pic from the first page of this thread showing which pins on the edge connector need what.  Tell me the game and I’ll play along.

 

[bulldawg]

Golden axe 2 on a 2mb 42 pin eprom. Donor pcb is RBI 93 42 pin 512kb pcb. So even if its 42 pin pcb still bend first 2 legs?

[pbj]

No… no…. Only bend the legs if the PCB is 40 pin.

I’m almost positive I have one of those RBI boards laying around.  I’ll convert to Golden Axe 2 and take pictures.

[pbj]

Are you using M27C400 or M274002?  4002 has the wrong pin out. 

Okay, assuming that you're using M27C400 and your PCB is the same as pictured here:



(found on this page:  https://www.pricecharting.com/game/sega-genesis/rbi-baseball-93 )

Pin 1 on the ROM is running to B7.  Pin 42 is being pulled high to 5V.  Your simplest fix is going to be cutting the trace on the back of the board for pin 42, and running a jumper wire from pin 42 to B8 on the edge connector.  That will tell the Genesis it's a 2MB EPROM.

 

[bulldawg]

Are you using M27C400 or M274002?  4002 has the wrong pin out. 

Okay, assuming that you're using M27C400 and your PCB is the same as pictured here:



(found on this page:  https://www.pricecharting.com/game/sega-genesis/rbi-baseball-93 )

Pin 1 on the ROM is running to B7.  Pin 42 is being pulled high to 5V.  Your simplest fix is going to be cutting the trace on the back of the board for pin 42, and running a jumper wire from pin 42 to B8 on the edge connector.  That will tell the Genesis it's a 2MB EPROM.

Im using m27c160 on this one. I should have mentioned this is different from the other one I was working on. But that would make sense why the other board is not working being 4002 is different pinout.

[pbj]

I've read that the only difference between an EPROM and OTP ROM is the quartz window.  If you can somehow expose the internals, you can erase a OTP.




I tried my soldering iron at 900 degrees and couldn't cut through the housing. 

Tried the dremel on another chip.  It exposed the internals but I think went a little too far.   



Still working on a process... surely something will eat away the housing gently.   

[bulldawg]

Are you using M27C400 or M274002?  4002 has the wrong pin out. 

Okay, assuming that you're using M27C400 and your PCB is the same as pictured here:



(found on this page:  https://www.pricecharting.com/game/sega-genesis/rbi-baseball-93 )

Pin 1 on the ROM is running to B7.  Pin 42 is being pulled high to 5V.  Your simplest fix is going to be cutting the trace on the back of the board for pin 42, and running a jumper wire from pin 42 to B8 on the edge connector.  That will tell the Genesis it's a 2MB EPROM.

Well this one is going to be a no go. I was redoing my connection from pin 42 to b8 and the pad lifted up. Oh well. Thanks anyway.

[pbj]

Put a jumper wire on pin 42 and try it pulled to ground and see if it boots.  If it doesn't, tie it back to 5V.  If that doesn't work, tie pins 1 and 42 together, and then try 5V and then ground.  One of those combinations will make it work.

If you have 42 pin holes on the PCB, there's no need to lift legs, but you may have to cut traces to properly isolate the pins before you add the jumper wires.


Here's a Forgotten Worlds (512Kb ROM) on a 40 pin PCB burned to a 2MB 42 pin EPROM.  I've lifted legs 1 and 42, jumped them together, and jumped to the 5V on the back of the PCB.

[bulldawg]

Put a jumper wire on pin 42 and try it pulled to ground and see if it boots.  If it doesn't, tie it back to 5V.  If that doesn't work, tie pins 1 and 42 together, and then try 5V and then ground.  One of those combinations will make it work.

If you have 42 pin holes on the PCB, there's no need to lift legs, but you may have to cut traces to properly isolate the pins before you add the jumper wires.


Here's a Forgotten Worlds (512Kb ROM) on a 40 pin PCB burned to a 2MB 42 pin EPROM.  I've lifted legs 1 and 42, jumped them together, and jumped to the 5V on the back of the PCB.

Pin 42 to ground worked. Thanks alot.

[bulldawg]

Where are you picking up 5v from? That might be what I need to fix that other pcb. The 40 pin one I have.

[pbj]

Yellow is a hypothetical jumper from pin 42 to 5V.  Blue is a jumper to ground.  Some games/chips work with one, some with the other.  Try both.

[bulldawg]

So pin 1 and 42 to 5v no go, but both to ground and I get the sega screen followed by a red screen. So some progress. This is the 40 pin nhl 93 pcb with the trace cuts and jumpers. Also just to note I have a socket installed and the legs are down but not touching pcb. I have tmnt hsh 1 mb image on 2mb eeprom.

[pbj]

Cut the traces above A8 and A9 above your jumper wires.  You don’t want them connecting to any of the SRAM stuff.

If that doesn’t do it, reflow your socket connections.  Particularly top row towards the middle.

You’re positive the checksum is correct?  Red screen is usually checksum error.

You’re close.

 

[bulldawg]

Cut the traces above A8 and A9 above your jumper wires.  You don’t want them connecting to any of the SRAM stuff.

If that doesn’t do it, reflow your socket connections.  Particularly top row towards the middle.

You’re positive the checksum is correct?  Red screen is usually checksum error.

You’re close.

 

So I cut the traces above a8 and a9, I checked all the pins for continuity and all good and I dumped the rom and test in kega and it works but still no go.

[pbj]

Open the rom header on the rom suite program and make sure it matches.  I can post a pic tomorrow.  Or just email it to me and I’ll test. (Pinballjim at hotmail dot com)

[lilshawn]

you wonna try SNES games next? they are super easy! ive done about 2 dozen games. same same, remove rom, burn a new one byte swapped... couple jumpers to swap 2 legs, and done.

[pbj]

Through a combination of work incentives and class action lawsuit payouts, I managed to pick up an SD2SNES for about $40 out of pocket.  That has instant loading, save state support, etc etc.  Should be here by the end of the week.

I also don't really feel the urge to do the SNES thing like I did Genesis, and you get into complications like buying expensive donor cartridges or making new expensive blanks.  Star Fox 2 is slightly tempting, but even that's gonna be about $20-30 each and you have to snuff another game to do it.  I've got a few tire kickers on that one but nobody's committing.  I see people selling those for ~$60 and frankly that's probably worth it if you want one.

[lilshawn]

I managed to pick up an SD2SNES for about $40 out of pocket.

i would buy one of those carts if they didn't want 225 bucks for the latest everdrive "FXpak pro" version ones... and 199 for the n64 one to while i was at it.

that said i've probably spent over 200 bucks on used carts and roms to make the ones i have now. c'est la vie 

[pbj]

$105 for a Chinese version.  It’s not even a bootleg as it was all open source.

 

[bulldawg]

Open the rom header on the rom suite program and make sure it matches.  I can post a pic tomorrow.  Or just email it to me and I’ll test. (Pinballjim at hotmail dot com)

So I burned another eprom with your image and still no go. But I tried that rom in another donor pcb and it worked. Something else im missing on the first pcb.

[bulldawg]

On a side note this is all the ones I've been successful with thus far, except mk im waiting on m27c322 eproms.

[pbj]

I may actually cry a little.  I'm glad you got TMNT working.

Here's how I do my labels.  It took me dozens of attempts to work out this method.  You may consider it.  I've actually reprinted and replaced a bunch of mine.

First buy 100 full sheet mailing labels off the ebay for ~$15 and print six labels to a sheet:



(I like to use the leftover white space to make EPROM labels and also has a note in there about what sizes the SEGA/EA labels should be)


You can do this before or after the clearcoating, but peel the backing side and cut slits underneath where it rests on the labels.  Keeps you from nicking them up trying to peel them later.



Tape it to the vertical side of a cardboard box.  One misty coat so you don't make the ink run.  Wait an hour, give it a second coat.



Then cut them out as straight as you can manage.  Run a sharpie sideways along the sides.  You can see I've done about half this edge in this photo:



Here's the whole side done:



Then when you slap it on the shell, you don't have a white leading edge:



I've got a multicolor set of sharpies, so I use red/blue/orange/whatever as most closely matches the art.

 

(and this is an extra Cave Story cartridge.  who wants it?  )

[emphatic]

That's some next level label work. 

[bulldawg]

I may actually cry a little.  I'm glad you got TMNT working.

Here's how I do my labels.  It took me dozens of attempts to work out this method.  You may consider it.  I've actually reprinted and replaced a bunch of mine.

First buy 100 full sheet mailing labels off the ebay for ~$15 and print six labels to a sheet:



(I like to use the leftover white space to make EPROM labels and also has a note in there about what sizes the SEGA/EA labels should be)


You can do this before or after the clearcoating, but peel the backing side and cut slits underneath where it rests on the labels.  Keeps you from nicking them up trying to peel them later.



Tape it to the vertical side of a cardboard box.  One misty coat so you don't make the ink run.  Wait an hour, give it a second coat.



Then cut them out as straight as you can manage.  Run a sharpie sideways along the sides.  You can see I've done about half this edge in this photo:



Here's the whole side done:



Then when you slap it on the shell, you don't have a white leading edge:



I've got a multicolor set of sharpies, so I use red/blue/orange/whatever as most closely matches the art.

 

(and this is an extra Cave Story cartridge.  who wants it?  )

That's some quality work.

[bulldawg]

Got my m27c322 roms today and programmed Mortal Kombat arcade edition and it works until the end of round one and freezes. Donor Cart was nfl qb club 96 which is a 4mb cart and my rom is 4mb any ideas?