17 Jan 2018

Sega System 24 desuicide and floppy conversions to ROMs (part 2)

Thanks to a German collector I've been able to put my hands on a System 24 boardset.
Better than that he actually sold me a motherboard, a romboard, a floppy controller and floppy drive!
I'm now fully equipped.

After building a System 18/24 adapter to JAMMA and hooking the board to a video converter (remember it's 24kHz) I was finally able to test my work :










All my decrypted games work ! Except for Rough Racer which got stuck on the loading screen (not sure it's an error in the code or a problem with the floppy emulator).

I still need to test my ROMs to floppy conversions. I've also designed a Multi game kit (more information about that to come).

10 Jan 2018

Sky Soldiers - SNK 1988 (repair log)

After a first visual inspection I noticed someone previously worked on the board: 2 capacitors have been replaced and 2 resistors have been reflowed. Was it part of a previous repair or an attempt to repair the current problem? I will never know.
Anyway, I also found a cut trace I patched.


I powered the game, it was stuck on the initial screen (the one before the game starts its RAM/ROM tests):


I probed the main CPU, reset signal was toggling between high and low: again game was stuck in a reset loop, watchog was barking, no valid code was executed. With the help of my logic probe I found 4 data lines were behaving weirdly. I identified few chips on the data bus: two 8 bit RAMs (LSB/MSB), 4 ROMs, few TTLs (mainly LS245 Hitachi brand, i.e. rock solid) and two weird SIL custom chips used for inputs (29 pins). ROMs turned out to be good. I pulled the RAM connected to the 4 suspicious data lines but it was OK too. The remaining TTLs on the data bus were all Hitachi brand so I was pretty confident they were good too. I was left with the two big SIL29 custom chips marked "ALPHA INPUT 87". I pulled them, few pins were broken on each. As often I tried to run the game without them looking for any change: the game booted! Obviously I couldn't play it because of the missing controls. Quite weird the game doesn't boot with the chips in place with missing pins but plays fine with them removed. I repaired the broken pins with resistor legs and game was fully functional:


Game fixed.

3 Jan 2018

Conversions on Irem M107 hardware (Dream Soccer '94 to Air Assault)

M107 hardware is very close to M92 and sound encryption is identical.
So I've simply reused the tools I created for M92 to convert the sound ROMs of Air Assault to be used on Dream Soccer '94.

Patched files for sale, contact apocalypse-mods@outlook.co.nz






Also available:

- Air Assault/Fire Barrel
- Dream Soccer '94
- Kick for the goal
- World PK Soccer





28 Dec 2017

Chelnov/Atomic Runner - Data East 1988 (repair log)

Some repairers have what they call a "too hard to repair" pile. I don't understand this concept, to me boards are either repairable or not.
Not repairable means a custom chip is faulty (so far I've always found a solution to circumvent faulty security chips).
Instead I have a "too long to repair" pile. In this pile you find boards I know I can repair but requiring a lot of time.
This Chelnov board was one of them.



First I swapped all the ROMs, PROMs and security chip on a Karnov board to confirm they were ok. Test was sucessful (meaning all ROMs, PROMs and security chip were good).

Then I started to repair the bottom board as it contains the only custom chip of the boardset, possibly being a repair killer.
The game was victim of the Fujitsu plague: I removed and replaced all Fujitsu TTL chips of the bottom board (only 5 of them) and then tested the board with the Karnov top board: it was now fully working.

This is where I left the repair for one year and a half. At this point I knew I could fix the board as all the ROMs, PROMs and security chip were tested OK, so as the only custom chip on the bottom board. I was left with a top board heavily populated with Fujitsu TTL chips and by probing few of them I could tell the damage was extensive...

When I got back to it I moved on the top board with the same treatment: I pulled all the Fujitsu TTL chips (probably 80+).
This took me several hours... (remember "too long to repair").
Out of curiosity I tested them on my programmer and 52 turned out to be bad...

Ok, after that game was still dead, showing only a garbage screen.
I found reset signal of the main CPU was too low to be considered as being a high level (below 3V): 68k was faulty and probably partially grounding/dragging down the signal.
I installed a new 68k, reset signal was now healthy but behaviour of the game didn't changed.

So I started to probe the data signal of the main CPU and found there was activity only for a fraction of second after power up.
To me this was a problem with code execution. All the TTL on buses were new now so I checked traces between the program ROMs and RAMs but they were all OK.
Last probable culprits in line were the work RAMs, unfortunately activity didn't last long enough to see anything on my old analog scope.
So I pulled them and both revealed bad on my programmer. Once replaced the game booted!



With sound, controls, texts and background but sprites were totally absent.
Probing TTL chips I found the outputs of the only 7425 (Texas Instruments) on the board were floating: sure enough it was bad.
I replaced it and finally obtained a fully working game.


Game fixed.


- 1 * CPU 68000
- 2 * work RAMs (6264 type)
- 1 * LS08 (Fujitsu)
- 2 * LS10 (Fujitsu)
- 1 * LS30 (Fujitsu)
- 3 * LS32 (Fujitsu)
- 6 * LS74 (Fujitsu)
- 1 * LS125 (Fujitsu)
- 1 * LS138 (Fujitsu)
- 9 * LS153 (Fujitsu)
- 7 * LS157 (Fujitsu)
- 1 * LS174 (Fujitsu)
- 3 * LS194 (Fujitsu)
- 11 * LS245 (Fujitsu)
- 4 * LS283 (Fujitsu)
- 2 * LS374 (Fujitsu)
- 1 * 7425 (Texas Instruments)

20 Dec 2017

Samurai Shodown RPG (Neo Geo CD) - English translation

This is a project I've started few years ago but never completed, I've sunk so many hours in it...
If I remember correctly scenario 1 is fully translated for all characters.
I estimate at least 100h are still needed to release a beta version with both scenarios translated. Then more time will be needed to fix bugs, typos, funny spacings, etc.

Download link (audio files not included):





13 Dec 2017

Sega Master System 2 (repair)

This console was given to me as faulty.
It wasn't doing anything (balck screen, no sound).
I opened it and was greeted by a sticker with hearts on it, someone weird had opened the console before and left a mark.


First thing I did was to check the voltage regulator: 5V, fine.
Then I started to probe signals on the CPU, work RAM, and BIOS ROM: pin 22 (signal /EXTM2 which I consider being equivalent to /CE) was floating on the BIOS ROM.
According to the schematics it's generated by the custom chip IC5 on pin 12 and is also connected to pin 11 of the cartridge connector:



Connection between IC5 and the cartidge port was fine however the one from the cartridge port to the BIOS ROM wasn't. I patched it with a piece of kynar wire :


And tested the in-built game :


And a catridge game :


Console fixed.

6 Dec 2017

Sega Mark III - Sega Sports Pad game hack


An other Sega oddity. As far as I know only 3 games were developed to make use of the Sega Sports Pad which is a kind of trackball device. Again, it's impossible to play them with a standard pad.
I've made a hack for Great Ice Hockey to be able to play with standard controllers (supports both players).


Great Ice Hockey:


Download link:



Cheksum has been fixed so the game runs fine on a US/EUR console (if someone ever wants to make a cartmod).


Technical part:
Horizontal speed for player 1 is stored in RAM @ $C018
Vertical speed for player 1 is stored in RAM @ $C019
Horizontal speed for player 2 is stored in RAM @ $C01A
Vertical speed for player 2 is stored in RAM @ $C01B