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Author Topic: Sega Mega-Tech Restoration  (Read 1105 times)

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mourix

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Sega Mega-Tech Restoration
« on: January 27, 2024, 05:56:29 pm »
Been more active on UKVAC lately but let's not forget this forum we all grew up with. I present you this original Sega Mega-Tech :cheers:

Up front, things are just your basic 30 years of wear and tear. Gotta replace locks, CPO, buttons and clean a whole bunch:



Up back and around, things are not as nice..The rear door is missing, and the backpanel is severely kicked in. Additionally, the bottom plate also has a crack so the entire cab is wobbly. I'm on the fence whether to stabilize the backpanel or make a new one entirely:



When I picked up this machine I immediately noticed the main monitor was not original. There should be two Hantarex MTC9000's in there, but the main screen is a Kortek KTM-F. After sliding down the cab from the second floor we found this green connector on the floor. Later at my home the main screen did not light at all. You know why? I figured out the green connector is the AC in for the original MTC9000, and the red and white wires are the AC in on the Kortek. I definitely want to improve this. For now, it literally just had to be shoved in there:



So that leaves me with this:



Electrical inspection time:
The main board works with all 8 original games.
The sound is really tinny. Maybe a main board recap needed.
The power supply -12V line measures -16V.
The menu screen is very sharp but way too bright.
The main screen is quite blurry. Not sure if that's dirt or focus. Also the adjustment board of it had a broken pot.
Finally, all lamps are missing....

I've got big plans for this machine. At the end of the run, it will be almost like new.
As a hardware engineer, I also want to design some custom game carts for it. This time open source for everyone :)

To be continued...
 
« Last Edit: January 27, 2024, 06:00:33 pm by mourix »

mourix

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Re: Sega Mega-Tech Restoration
« Reply #1 on: January 27, 2024, 05:57:36 pm »
Mini update.

Ordered all the light bulbs and locks. Also, I found out why the monitor was so blurry:


mourix

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Re: Sega Mega-Tech Restoration
« Reply #2 on: January 29, 2024, 05:35:31 pm »
Lights came in:



I also adjusted both monitors. Things are looking pretty great in a dimly lit room:


pbj

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Re: Sega Mega-Tech Restoration
« Reply #3 on: January 30, 2024, 09:00:17 am »
Never saw one of these in the wild, pretty cool looking.  Looks like the cartridges are pretty easy to bootleg:

https://www.tindie.com/products/caiusarcade/sega-mega-tech-reproduction-cart-blank-board/

Surely other games have been ported to that system by now?

EDIT - looks like you can run an Everdrive on them...

https://mega.nz/folder/5mZGTQZQ#mDAuPaSu1BSt6G0WRXTMqQ
« Last Edit: January 30, 2024, 09:09:15 am by pbj »

Mike A

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Re: Sega Mega-Tech Restoration
« Reply #4 on: January 30, 2024, 09:01:37 am »
That thing looks cool.

I am not familiar with it.

Thank you for posting.

mourix

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Re: Sega Mega-Tech Restoration
« Reply #5 on: January 30, 2024, 12:24:28 pm »
Never saw one of these in the wild, pretty cool looking.  Looks like the cartridges are pretty easy to bootleg:

https://www.tindie.com/products/caiusarcade/sega-mega-tech-reproduction-cart-blank-board/

Surely other games have been ported to that system by now?

EDIT - looks like you can run an Everdrive on them...

https://mega.nz/folder/5mZGTQZQ#mDAuPaSu1BSt6G0WRXTMqQ

The Mega-Tech did not get a wide US release.

I got many open source hardware ideas brewing. There are Mega Drive or SMS based original carts to be remade ofc. But even a Mega-Tech to original Mega Drive or Master System cart converter board should be possible :burgerking:

Right now I'm trying to get all the data on the Arcade Otaku wiki. Lots of reverse engineering to do.
« Last Edit: January 30, 2024, 12:26:39 pm by mourix »

mourix

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Re: Sega Mega-Tech Restoration
« Reply #6 on: February 05, 2024, 03:44:33 pm »
This weekend I stabilized the foundation. Basically the entire side was cracked and wobbly:



I hid 6 long screws below the metal protection bars along the bottom. For good measure I put some extra metal braces, long screws for the feet and lots of wood glue. This is now most definitely the strongest section of the entire cab:



Mike A

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Re: Sega Mega-Tech Restoration
« Reply #7 on: February 06, 2024, 05:34:44 am »
Keep it coming.

Love it.

mourix

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Re: Sega Mega-Tech Restoration
« Reply #8 on: February 08, 2024, 11:39:04 am »
Documentation sharing time

The cab included a written manual for the Hantarex MTC9000, but the changed main screen was a Kortek KTM-F with no manual available online.
I ended up tracking down the missing manual on UK ebay. Damn, post brexit import duties and shipping cost were higher than the item...

Anyways, here we are:



After a night of scanning and Photoshop now free for everyone:
Kortek Sejoo KTM-F Technical Manual Eurocoin Vision Series
Hantarex MTC 9000 Service Manual 14"-20"
Hantarex MTC9000/A Circuit Diagram 14"-20"
« Last Edit: February 08, 2024, 11:43:32 am by mourix »

mourix

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Re: Sega Mega-Tech Restoration
« Reply #9 on: February 15, 2024, 12:13:16 pm »
I got many open source hardware ideas brewing. There are Mega Drive or SMS based original carts to be remade ofc. But even a Mega-Tech to original Mega Drive or Master System cart converter board should be possible :burgerking:

Right now I'm trying to get all the data on the Arcade Otaku wiki. Lots of reverse engineering to do.

Sneak peek at what's (home)brewing:

« Last Edit: February 15, 2024, 12:17:33 pm by mourix »

mourix

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Re: Sega Mega-Tech Restoration
« Reply #10 on: February 22, 2024, 09:49:39 am »
Front kickplate cleaned up well after some magic eraser and black permanent marker action. Also added new locks, screws and obligatory Sonic keychain.



The Dutch regulatory sticker plexiglass was cracked up pretty bad. To keep it stock, I just 3D printed some washers to hide most of the damage.

« Last Edit: February 22, 2024, 10:02:24 am by mourix »

mourix

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Re: Sega Mega-Tech Restoration
« Reply #11 on: February 23, 2024, 04:19:25 pm »
Currently I have reverse engineered both the Megadrive and Master System based carts. These are on the way from China as we speak:



I'll do a full write up once I got them in and tested. The plan is a Github for everyone to make their own.

mourix

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Re: Sega Mega-Tech Restoration
« Reply #12 on: February 27, 2024, 04:02:59 pm »
In today's update: a warning for people wanting to recap the Mega-Tech PCB.

I wanted to try a recap because my cab sounded like a smartphone. So I made the cap list here and got to work.

I own a decent soldering/desoldering station so usually it's a breeze, but not this time. This board got all the difficulties.. Multilayer ground planes, small through holes, bent leads and thin traces right next to cap pads.

After hours of soldering it does look nice though:



However this is what I was greeted with when I plugged it in. Crapp.. Back to debugging I guess.



NES4Life has a nice write up on this so I knew which area to look at. Finally found the issue:



I added one blue botch wire to the green factory botch wire seas:



But hey, we are back!



But... now the left speaker was dead. After a bunch of digging that was a 3mm track without a connection so a solder blob got it back.

And now I own a nicely recapped Mega-Tech that almost killed it...and still sounds like a smartphone. I guess it was 80's speaker quality all along :dunno

mourix

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Re: Sega Mega-Tech Restoration
« Reply #13 on: Yesterday at 02:47:07 pm »
Progress update on the homebrew. I want more games in my collection, but even sports ones are getting expensive now. There are some guys selling repro gamecart PCBs, but I want open source everything ;)

For the whole library, we need both a Mega Drive and Master System based cart. The 171-5782 is the common 4M Mega Drive cart, and the 171-5783 is the common 1M/2M Master System cart. 

To get both, these were the sport game victims of the day:



After taking them apart and removing every component, I made scans of both sides of both boards and lined them up in Photoshop.



Based on those master Photoshop files, I traced every track in Altium Designer software until I had an almost 1:1 reproduction of the layout and schematics to accompany.



After lots of tidying up I ordered 10 pieces each from JLCPB. This showed up yesterday:


« Last Edit: Yesterday at 05:22:31 pm by mourix »

mourix

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Re: Sega Mega-Tech Restoration
« Reply #14 on: Yesterday at 03:15:00 pm »
The Sega Mega-Tech is pretty much a Mega Drive glued to an additional Master System that runs the menu screen. To make this duo work, the (same as home version) game rom is placed on a circuit board with an additional custom menu rom that contains the text to fill the menu pages.

The menu rom is a 27C256 that can be had from Aliexpress for cheap. So cheap even that my newly acquired T48 programmer freaked out because the Chip ID on them did not match the painted on manufacturer name.. But I got 3 out of 4 programmed in the end.



For the 4M Mega Drive games, a 27C400 EPROM fits in without modifications. But with me owning like 5 copies of Sonic 1, I just desoldered an original game cart chip.



I put it in the cab and was greeted with the following. YESSSSSSSS!!!!

« Last Edit: Yesterday at 05:23:25 pm by mourix »

mourix

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Re: Sega Mega-Tech Restoration
« Reply #15 on: Yesterday at 03:26:50 pm »
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 :)
« Last Edit: Today at 05:50:30 am by mourix »