Alien Syndrome PRE system 16 desuicide roms

Jason_971

Well-known member

Donor 2014, 2016
Joined
May 10, 2014
Messages
1,208
Reaction score
50
Location
Chesterfield, Michigan
Does anyone know if it's possible to desuicide a pre system 16 alien syndrome board? I can't seem to find decrypted roms anywhere for the pre system 16 board.

Thanks
Jason
 
I wasn't aware any of the Pre-System16 boards suicided. I thought that started with System16A or B?

No promises, but I'll check my stash to see if I have the ROMs.

Scott C.
 
I'm hearing that there is actually a pre system 16 board. Cannot confirm but I'm thinking it's just a one stack pcb. Not like the A and B boards that have the separate eprom board. Still investigating. If anyone can post a pic of an Alien Syndrome pre system 16 that would help out a lot to clear things up. Thanks
 
I'm hearing that there is actually a pre system 16 board. Cannot confirm but I'm thinking it's just a one stack pcb. Not like the A and B boards that have the separate eprom board. Still investigating. If anyone can post a pic of an Alien Syndrome pre system 16 that would help out a lot to clear things up. Thanks

It's 2 boards, similar to the system 16 with rom board on top, just larger bottom board.

 
Last edited:
So I guess there's really not a pre system 16 board. It goes 16A, 16A version 2.o, then 16B

Here's a reply from Chris at Sega Resurrection

There are 2 types of System 16A boardsets and one System 16B board (with
multiple rom board types).

What is called 'pre-system 16' boardset in mame is usually a 16A
boardset *without* the uPD7751 sound sample roms installed (ie the game
doesn't have samples). Mame lists the boards as 'no_7751' in the game
name, but there is physically a uPD7751 on the pcb, just no roms. The
game z80 sound driver doesn't write to the 7751 even though it's there.

The two types of System 16A boardsets are called 'System 16A' and
'System 16A Version 2.0'. One is a single boardset with a daughter board
which holds the eproms. The other (more typically seen in Japan) is a
two layer board with the roms on both boards.
The game code for the 16A games actually determines what boardset it's
running on and displays the correct eprom locations for each board style
in the test menu, which is cool.

Basically, the 'pre system 16' pcb doesn't exist. That help?
 
Just an update on my previous email reply to ebyrdpython.

I've checked the schems and each type is referred to this way.

The large single layer board is described as "System 16 V2.0",171-5335 with a date of 85.12.13 and the double layer board is "68000 V1.1 No 1", 171-5306,171-5307.

So, the larger board is V2.0, and the double layer board is V1.1. Kind of explains why I've seen many more Japanese games on the double layer board.

There are no markings on the double layer board saying System 16A anywhere. I don't have a single layer one to check. Maybe Sega came up with the name later. System 16b definitely has it on it.

All System 16A games will run on either hardware types. There is a memory location that returns either 0x0000 or 0xFFFF which the test mode uses to detect the pcb type. (This is undocumented in Mame)

Having said that, to convert between games (which is what people really want to know), you can only run a game with the same size eproms as the donor board as a PLD has to be changed to handle the different size as well as the jumpers.

Some games also need a 8751 instead of the NOP board which is used as the security.

Chris aka JunoMan aka Sega Resurrection
 
Back
Top Bottom