14 Feb 2018

Conversion SF2' to The Punisher (CPS1 no Q-sound)

After the Cadillacs & Dinosaurs conversion I thought i would be worth it to have a try at The Punisher. I've used the samples of The Chinese bootleg version named Biaofeng Zhanjing which are in fact Final Fight samples.

1) Material needed

1.1) If you use a 91634B-2 B-board (EPROM)
 - 12 * 27C4096 ROM (8 for the graphics and 4 for the program)
 - 2 * 27C010 ROM (audio)
 - 1 * 27C512 ROM (audio)
 - 1 * GAL16V8 (PAL)

1.2) If you use a 91635B-2 B-board (mask ROM)
 - 8 * 27C400 ROM (graphics)
 - 4 * 27C4096 ROM (program)
 - 2 * 27C010 ROM (audio)
 - 1 * 27C512 ROM (audio)
 - 1 * GAL16V8 (PAL)

2) ROMs and PAL burning

Now it's time to burn the files on the appropriated devices.

2.1) If you use a 91634B-2 B-board (EPROM)
 - ROMs 01/02/03/04/05/06/07/08/20/21/22/23 => 27C4096
 - ROM 09 => 27C512
 - ROM 18/19 => 27C010
 - PS63B_1a.jed => GAL16V8

2.2) If you use a 91635B-2 B-board (mask ROM)
 - ROMs 01/02/03/04/05/06/07/08 => 27C400
 - ROMs 20/21/22/23 => 27C4096
 - ROM 09 => 27C512
 - ROM 18/19 => 27C010
 - PS63B_1a.jed => GAL16V8

3) ROMs installation

All SF2' ROMs must be removed from the B-board.
The PAL named S963B at position 1A has to be removed too.
Double check you've put the devices the right way (the silkscreen should help you)!

3.1) If you use a 91634B-2 B-board (EPROM)
 - Install the ROMs in the corresponding socket (ROM 01 in socket 01, etc.)
 - Install the GAL16V8 in position 1A (where the S963B was)

3.2) If you use a 91635B-2 B-board (mask ROM)
 - Install the ROMs 01/04/05/08/09/18/19/20/21/22/23 in the corresponding socket (ROM 01 in socket 01, etc.)
 - Install ROM 02 in socket 03
 - Install ROM 03 in socket 02
 - Install ROM 06 in socket 07
 - Install ROM 07 in socket 06
 - Install the GAL16V8 in position 1A (where the S963B was)

4) Test

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

7 Feb 2018

Conversions on Jaleco Mega System 32

A not too well known system with only few titles but with great graphics for some of them.
It can be considered as Jaleco's answer to SNK's MVS as this system is composed of a mainboard in which you plug "cartridges" (which are more or less romboards with a plastic shell). Connection between the 2 isn't as easy as it is on MVS cause Jaleco didn't use edge connectors for its cartridges but high density connectors instead (similar to Capcom's CPS1 and CPS2 for instance).

Anyway, to prevent conversions, Jaleco implemented a custom chip in the cartridges for graphics decryption (texts and background only) with different decryption "parameters" between games. Some games share the same custom chip, thus can be converted straight forward, some others don't and even different versions (romsets) of the same game can use different custom chips.

Decryption algorithm being in MAME I first decrypted the files for gfx3 (background) and gfx4 (texts) for romset gratia (custom chip ref. SS92047-01). Then I made a second small piece of code for re-encryption. I chose to rencrypt the files for custom chip ref. SS92046_01 as it's used on Tetris Plus (romset tetrisp) and this game is quite common and cheap.

Finally I modified MAME's source to force it to use a different custom chip with romset gratia.

I changed this:
GAME( 1996, gratia,   0,        ms32, gratia,   ms32_state, ss92047_01, ROT0,   "Jaleco", "Gratia - Second Earth (92047-01 version)",

To this:
GAME( 1996, gratia,   0,        ms32, gratia,   ms32_state, ss92046_01, ROT0,   "Jaleco", "Gratia - Second Earth (92047-01 version)",

And tested the conversion successfully:

Next step is to test it on real hardware and maybe find a way to use decrypted files instead of re-encrypted ones to simplify things (no need to re-encrypt files for each different custom chip).

1 Feb 2018

Capcom 85H001 (sound module) reproduction - part 1

This module has been a real nightmare for me for years as its failure rate is quite high...
Unfortunately to save a game you have to sacrifice an other one as there's only one module per game.

I know of 3 different flavours (there might be more) which are interchangeable between games (I tested it personally) :
- Ceramic module without any marking: seen on Makaimura first run for instance
- Plastic module ref. 85H001 5I
- Plastic module ref. 85H001 5H

Affected games are (from the top of my head):
- Ghosts'n Goblins/Makaimura
- Avengers
- Legendary Wings/Aresu no tsubasa
- Section Z
- Trojan/Tatakai no banka
- Gun Smoke
- Black Tiger/Black Dragon

I already designed a replacement module which I tested on Trojan and GnG based on my observations and schematics of earlier games but I couldn't guarantee it was a 100% perfect replacement.
So recently I took the decision of decapping the ceramic module of my Makaimura first run (as it seemed a lot easier to me to dissolve ceramic rather than plastic).

Before soaking it in a basic (soda) solution I removed with a sharp knife the ceramic layer on top on each IC to be able to read references in case the soda washes them out (which it did!):

The module after a 24h soda bath (I added references):

I then drew the schematics and assembled a prototype with through hole parts:

And tested it successfully on real hardware!

Next step is to route a board the exact same size the original one with SMD parts.
Stay tuned!

The prototype tested on Trojan:

24 Jan 2018

Sega Mega-Tech & Mega-Play hack

Both systems are based on the Sega Megadrive console.
Here's a quick article about my finds on these systems.

1) Sega Mega-Tech

1.1) Cartridges
They contain 2 ROMs :
- One is the game itself. It can be a Megadrive ROM or Master System ROM.
- The second contains simply the name of the game to be displayed on the upper screen

1.2) Functionalities
Motherboard can hold up to 8 cartridges.
Player buy time rather than credits.

1.3) Compatibility
The only thing that forbids you to play Megadrive or Master System games on a Mega-Tech motherboard is the difference of pinout. With an adapter they play fine.
Region can be changed via dipswitches.

On the other side Mega-Tech games can be played on either the Megadrive or the Master System (depending of their origin) with an adapter.

2) Sega Mega-Play

2.1) Cartridges
They contain 2 ROMs :
- One is the game itself. It's a modified Megadrive ROM.
- The second contains instructions on how to play the game.

2.2) Functionalities
Motherboard can hold up to 4 cartridges.
Player buy credits.
Games are generally shorter (less levels) than their Megadrive counterparts, and harder (less lives, less time).

2.3) Compatibility
First you'll need an adapter to play Megadrive games on the Mega-Play.
However with the stock BIOS it displays an error message on the foreground:

I modified the BIOS to disable that.

Mega-Play games still plays fine with the modified BIOS so no need to swap it every time.
Region can be changed via dipswitches.

On the other side Mega-Play games can be played on the Megadrive with an adapter and a bit of hackery to disable inter-CPU exchanges and force credits.

Here's the link to Sonic The Hedgehog I've hacked to be played on the Megadrive:
It's a quick and dirty job, just leave the intro play and when level 1 starts it's up to you. Lives are almost unlimited.
Differences with the Megadrive version are:
- no Sega logo on start-up, no "Segaaaaaa" voice sample
- no select round or debug mode (present but disabled)
- game in Time Attack mode, time goes backward with for example 50s allowed to clear Green Hill Zone 1
- only 4 zones + final zone in the following order: Green Hill Zone, Spring Yard Zone, Star Light Zone, Scrap Brain Zone and Final Zone
- no bonus stage despite the fact the big ring is present, thus impossible to get chaos emeraulds
- based on the Japanese version with clouds moving on a different layer, blurry effect when in water, etc.
- high scores table present

All zones are present but some have been disabled. However you can enter them with a hack:

As they weren't meant to be playable in Time Attack mode time starts from 0 so you instantly die:

But are playable with a time hack:

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).

Rough Racer and Hot Rod require an additional I/O board (for analog steering wheels) ref. 834-6510 in order to boot past the warning screen. Rough Racer has been reported working by a collector having the dedicated I/O board. Thanks to him for his feedback.

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