Reverse engineering arcade PCBs for MISTer

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eskwadrat
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Reverse engineering arcade PCBs for MISTer

Postby eskwadrat » Sun Sep 08, 2019 9:24 pm

I design electronics controls around MCU/SoC for living for over two decades and PCB design comes with every project I was involved in so far. In the 90s I worked several years for nationwide game distributor mostly on casino style video slot machines and I remember seeing hundreds of arcade PCBs being pulled from liquidated arcades and scrapped. If only I knew retro arcade market would become once more among enthusiasts three decades later... but that's not where I am going here.

At one point of my later career I also used to reverse engineer multiple PCBs from customer Gerber's to editable artwork PCB projects w/schematic using Altium Designer and built-in CAMtastic. One project was to re-create artwork from bare pcb, customers did not have Gerber's either. The processing usually included following steps.

Desoldering all comments (professionally I was using 3rd party service but today at home I have no problem to use PACE desoldering station I own)
Photographing both sides to preserve overlays for later processing.
Removing overlay and soldermask to expose traces.
Photographing one layer, then another.
Importing to trace program (usually Corel Trace).
Importing traces bitmaps to CAMtastic
Converting bitmaps to Gerber.
Importing from CAMtastic to Altium
Running netlist creator.
Marking up components to cross with library.
Placing components in the schematic.
Running schematic update based on PCB netlist.

At this point we have schematic captured. It's usually between 90-100% accurate, this is where I continue analysis to close open loops. Then SCH job is done.

One of you guys would have to take it from here to code schematic into Verilog for MISTer use. While I could work on another arcade PCB reversal and help you in the meantime in case of a need.

My FPGA knowledge and application practice is insufficient to do effective coding, but I am comfortable reversing pretty much any two sided PCB to schematic. And I do own legal commercial license of Altium. With support from arcade fpga coders, I will be happy to: procure selected non-documented so far arcade pcb and reversed it to capture it's schematic.

For start, I have particular arcade games on mind, top 3 include:
Gorf
Terra Cresta
Tiger Heli

I am willing to start immediately on one of those. There are original arcade PCBs available on eBay at least for two of those. There is one for truly discounter price for no.2 but I can handle initial investment up to few hundred. Again, if there is anyone who would be willing to work on fpga core work from schematic I would deliver.

Let me know.

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bhamadicharef
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Re: Reverse engineering arcade PCBs for MISTer

Postby bhamadicharef » Mon Sep 09, 2019 8:22 am

Thank you for your suggestion and help. This will only work for 2 layer PCBs right.

I like the approach and reminded me of the work from Bald Engineer and his work
on the schematics of the Apple II ...

Please note that GORF's schematics is available from KLOV, so I think we can start from it first.
Brahim HAMADI CHAREF:: Singapore

warham
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Re: Reverse engineering arcade PCBs for MISTer

Postby warham » Mon Sep 09, 2019 9:12 am


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Re: Reverse engineering arcade PCBs for MISTer

Postby jotego » Mon Sep 09, 2019 9:13 am

If you produce the Terra Cresta schematics, I'll write the FPGA core and share the Patreon contributions for that core with you, that way you can shift a bit the cost of the process.

I already shared contributions for Popeye core with JAMMArcade. Furrtek also shared contributions to the NeoGeo work with me for my YM2610 core (as I have not charged for sound chips on my Patreon page, only game cores).
--
Source code of all my cores here.
My Patreon page here.

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eskwadrat
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Re: Reverse engineering arcade PCBs for MISTer

Postby eskwadrat » Mon Sep 09, 2019 2:08 pm

bhamadicharef wrote:Thank you for your suggestion and help. This will only work for 2 layer PCBs right.
(...)

Yes, this is limit for physical board. For reverse engineering from Gerbers, the layer count is irrelevant.

warham wrote:gorf docs are also in here
https://www.mikesarcade.com/arcade/manuals.html


Yes, indeed readable service manual w/schematic. Trouble is I see 3 chips called as "custom" and since I am not going to spend time on trying to reverse these, Gorf is off the table. But... Donkey Kong Jr schematic looks good w/o custom chips. I will dive and take a closer look.

jotego wrote:If you produce the Terra Cresta schematics, I'll write the FPGA core and share the Patreon contributions for that core with you, that way you can shift a bit the cost of the process.

I already shared contributions for Popeye core with JAMMArcade. Furrtek also shared contributions to the NeoGeo work with me for my YM2610 core (as I have not charged for sound chips on my Patreon page, only game cores).


Sound like a plan, thank you.
I just picked up one of the working TC pcb sets, awaiting delivery. I will get on this reversal work as soon as I receive it.
There is also another pcb set on eBay I am hoping to get. Both are different, the one I already purchased is "bootleg" version while the one I am hoping also tot get (backup) is told as genuine one form Nichibutsu. The last one uses 4 EPROM chips (4 sockets are empty) while the bootleg shows all 8 sockets populated. Either way, the "game is on". Will update on the progress soon.

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