Sega Mega-Tech Restoration

[mourix]

The Master System cart is a bit more complicated than the Mega Drive. The menu rom is the same 27C256, but the games themselves have special roms with built in mapper logic. This means the only easy way to make a repro is to remove a rom from an original Master System game as eproms won't work.

Hence, the game rom stealing continued:

But the results continued too

There is still one mystery left. The original Mega-Tech cart has connections to ground a bunch of rom pins, but the traces are strategically drilled out on the 1M rom cart I had. Interestingly enough they also exist and are drilled out on the 2M Master System console games I own. I've experimented a bit with a cheap sports game rom and it has the same power consumption and behavior no matter if the ground connections existed or not... Does anyone have an idea about this, or is someone able to open up a 2M Mega-Tech cart to verify?

I definitely have some more game making and experimenting to do.

Once I am 100% confident on the design I will make a Github release and forum thread

 

[Adamski]

You sir are a genius!
Respect and thank you for your efforts

 

[Adamski]

So my PCB is coming back in the next few days after random switching off and on,menu glitches and spontaneous test screen appearance.I sent it to Luke @ Retrosix who specialises in Megatech.I thought I would share his findings with you all.Makes interesting viewing!

https://www.tiktok.com/video/7335920689041493281

 

[mourix]

So my PCB is coming back in the next few days after random switching off and on,menu glitches and spontaneous test screen appearance.I sent it to Luke @ Retrosix who specialises in Megatech.I thought I would share his findings with you all.Makes interesting viewing!

https://www.tiktok.com/video/7335920689041493281

This is interesting. One issue though.. It definitely is not a 2 layer pcb.

 

[mourix]

The Mega-Tech carts are housed in Japanese Mega Drive shells. To make the repros complete I got this from Aliexpress:

To make it fit, some small studs in these shells had to be cut and the DIP sockets removed. But after putting it in, something was off. It was like the edge connector is too short.

To make sure, I opened the original soccer cart back up. Yup, too short.

But now I put my repro in the original shell. See? My cart is correct:

So now I am in need of input. Do we adjust the PCB design release for these crappy shells? I am a tad unsure.

 

[david656]

@mourix the work you are putting in here is absolutely fantastic and very close to my heart in the level of detail and quality you are outputting. 2 questions for you, how much is the sonic 2 cart? if I asked you nicely and we came to an arrangement would you help to replicate a simple PCB in the way you've shown here or show me how to do it

 

[Flyback2021]

@mourix fantastic work !
Loving the detail and what you are striving to produce.
How close in look and feel are the Ali express cases to the original mega tech carts . If close then perhaps adjust the pcb design ?

 

[Flyback2021]

@mourix the work you are putting in here is absolutely fantastic and very close to my heart in the level of detail and quality you are outputting. 2 questions for you, how much is the sonic 2 cart? if I asked you nicely and we came to an arrangement would you help to replicate a simple PCB in the way you've shown here or show me how to do it

I think Sonic 2 could be £300 possibly more ?have not seen one for sale in a few years. Certainly one of the most sought after on the system. I unfortunately don’t have one anymore otherwise I would certainly lend for this project. I have found quite a few duplicates possibly 20/30 titles from when I brought 2 mega techs 10 years ago but unfortunately not sonic 2.

 

[mourix]

@mourix the work you are putting in here is absolutely fantastic and very close to my heart in the level of detail and quality you are outputting. 2 questions for you, how much is the sonic 2 cart? if I asked you nicely and we came to an arrangement would you help to replicate a simple PCB in the way you've shown here or show me how to do it

As flyback said, the Sonic 2 is almost unobtanium.
I have replied your PM and definitely want to look at your PCB

 

[mourix]

@mourix fantastic work !
Loving the detail and what you are striving to produce.
How close in look and feel are the Ali express cases to the original mega tech carts . If close then perhaps adjust the pcb design ?

Very close. I have decided make seperate "Redux" versions of the original PCBs that have longer connectors and tweaks to make reproductions easier.

I think Sonic 2 could be £300 possibly more ?have not seen one for sale in a few years. Certainly one of the most sought after on the system. I unfortunately don’t have one anymore otherwise I would certainly lend for this project. I have found quite a few duplicates possibly 20/30 titles from when I brought 2 mega techs 10 years ago but unfortunately not sonic 2.

By chance, are you able to open up and photograph an Alien Syndrome or Shinobi cart on both sides? It would help me verify the drilled out connection situation.

 

[Flyback2021]

Very close. I have decided make seperate "Redux" versions of the original PCBs that have longer connectors and tweaks to make reproductions easier.


By chance, are you able to open up and photograph an Alien Syndrome or Shinobi cart on both sides? It would help me verify the drilled out connection situation.

Yes, should be able to do this over weekend

 

[mourix]

Control panel time.

This is the starting point. Cracked/faded CPO with very crunchy buttons. Definitely needed a refresh.

Now to continue the insane open source project, I got another Canon Lide 110 for €3,50 and followed my own tutorial again.
I put together the scans and made my own reproduction. This came in a week later:

Finally I put the CPO on together with legit IL PSL-H pushbuttons and Cherry D44X switches I had to import from France as Dutch stores only sell Ali imports..
Disassembly was a paint with lock nuts, glued buttons amounts of CPO glue that should be illegal. The results do speak for themselves though

Of course, the 300DPI print file is available for everyone

 

[Flyback2021]

Top work as we have come to expect ! Bet that was a sweet moment seeing the panel restored and back together !

 

[tb2000]

Excellent thread! Very interested to see the finished restoration. It's surprising the amount of these cabs that have come up for sale in the past 6-12 months. I have a spare pcb and a couple of carts from a cab with a near complete collection (there were a few doubles of some carts) that me and Olly (muddymusic) had for a while before selling it on so would probably like to get another (possibly empty) Megatech cab at some point.

 

[Flyback2021]

Excellent thread! Very interested to see the finished restoration. It's surprising the amount of these cabs that have come up for sale in the past 6-12 months. I have a spare pcb and a couple of carts from a cab with a near complete collection (there were a few doubles of some carts) that me and Olly (muddymusic) had for a while before selling it on so would probably like to get another (possibly empty) Megatech cab at some point.

Yes, there certainly has been a few for sale in UK during last year or so. Brought my first 2 about 9 years ago, moved onto other collecting things and let them go with later regret but kept a lot of games luckily as they have dried up since. Then picked up another off eBay Years later which had been restored by John Ward. Nice video of his machine restore on YouTube I believe. Great system and goes nicely next to the playchoice. Have a project Megatech with motherboard and monitors but need to do some testing on it before I decide what to do with it.
Hopefully this excellent thread will create new interest for the system plus all the open source @mourix is lovingly working on.

 

[Mr20to5]

Control panel time.

This is the starting point. Cracked/faded CPO with very crunchy buttons. Definitely needed a refresh.

Now to continue the insane open source project, I got another Canon Lide 110 for €3,50 and followed my own tutorial again.
I put together the scans and made my own reproduction. This came in a week later:

Finally I put the CPO on together with legit IL PSL-H pushbuttons and Cherry D44X switches I had to import from France as Dutch stores only sell Ali imports..
Disassembly was a paint with lock nuts, glued buttons amounts of CPO glue that should be illegal. The results do speak for themselves though

Of course, the 300DPI print file is available for everyone

Brilliant stuff. Great attention to detail (again). Original CPO too far gone to save unfortunately, but you've done an amazing job. Thanks for sharing! 👍

 

[ChrisBEANS]

Fantastic thread. Really enjoyed reading through this.

I’ve never seen one of these in the wild, but there’s something ‘special’ about it.
The second screen with the additional info etc is glorious, and just the novelty of playing these familiar home console games on a cab is great.

I have one of the JAMMA to console boards (apologies to the guy on here who designed and built it, I’ve entirely forgotten what it’s called but I’ll edit in a bit to give proper credit!) and even playing these games that way is exciting and novel, so playing on a dedicated cab must be brilliant fun!!

Excuse the noob question, but if these cabs have specific ROM boards for the menu, then will the proposed adapter that allows use of home carts give a game name on the menu?
If it’s a game that was never released for the megatech, then where is that game name stored?

 

[Flyback2021]

Yes, should be able to do this over weekend

@mourix hope this helps, any further info let me know.
best Ant

 

[mourix]

@mourix hope this helps, any further info let me know.
best Ant

Thank you!! That verifies that the hole exist even in the boards with the bigger 2Meg roms.

These are my planned "redux" boards:


With these I have made the following changes:

• Remove unused caps and jumpers.
• Increase edge connector length by 1mm to give fake shells a change.
• Mega Drive PCB: add support for 42-pin EPROMS to support up to 32Meg games.
• Master System PCB: remove the now verified drilled out connections from PCB.

 

[mourix]

Fantastic thread. Really enjoyed reading through this.

I’ve never seen one of these in the wild, but there’s something ‘special’ about it.
The second screen with the additional info etc is glorious, and just the novelty of playing these familiar home console games on a cab is great.

I have one of the JAMMA to console boards (apologies to the guy on here who designed and built it, I’ve entirely forgotten what it’s called but I’ll edit in a bit to give proper credit!) and even playing these games that way is exciting and novel, so playing on a dedicated cab must be brilliant fun!!

Excuse the noob question, but if these cabs have specific ROM boards for the menu, then will the proposed adapter that allows use of home carts give a game name on the menu?
If it’s a game that was never released for the megatech, then where is that game name stored?

These are definitely fun, especially if you own/make many carts.

These are my planned converters:


As you see, there is still one EPROM needed on the PCB. This is the one that contains the text and layout of the menu item.
I am about halfway done with ROM editing for the Mega Drive menu, which will look something like this regardless of the home game you plug into the top: