RCM - RETRO COMPUTER MUSEUM

GENERAL => ARCADE => Topic started by: porchy on July 28, 2010, 08:36:17 PM

Title: SEGA System 16 board
Post by: porchy on July 28, 2010, 08:36:17 PM
Got a Golden Axe game running on SEGAs System 16 motherboard recently.
Its not a JAMMA pinout so quickly rushed together a minimalistic adapter, enough to get it up and running for tests.
On firing it up there was no sound, this ended up being a fried Z80
There was also no inputs registering. The inputs go through some NEC2501 IC's of which there is nothing in the way of datasheets for. By chance I removed one of these chips and the silkscreen gave me an alternative to look for of TLP521-4, a photo transistor. Not seen these on any other boards other than SEGA yet.
Long story short, turns out that these babys need a seperate +5v supply where as the pinout just states the pin as another +5v. In my laziness I only hooked up a couple of the +5v lines and GND lines thinking they would all be connected like in JAMMA.
Title: Re: SEGA System 16 board
Post by: AndyRCM on July 28, 2010, 08:40:38 PM
;) Nice work in finding out that mate! ;) System 16 boards mmmmm nice! Don't you just love Sega stuff! ;)
Title: Re: SEGA System 16 board
Post by: porchy on July 28, 2010, 08:41:41 PM
I really like SEGA stuff. A lot of there hardware is greatly under rated
Title: Re: SEGA System 16 board
Post by: Phu on July 29, 2010, 09:05:02 AM
an alternative to look for of TLP521-4, a photo transistor. Not seen these on any other boards other than SEGA yet.
Long story short, turns out that these babys need a seperate +5v supply where as the pinout just states the pin as another +5v. In my laziness I only hooked up a couple of the +5v lines and GND lines thinking they would all be connected like in JAMMA.

Sounds like you have an opto-isolator there. Someone is really keen to keep two sections electrically isolated (hence the opto-isolator to get signals from one to the other). Thats a somewhat unusual requirement for an arcade board..... any ideas why it's needed?

-- Richard
Title: Re: SEGA System 16 board
Post by: Womble on July 29, 2010, 12:12:32 PM
It initially struck me as somewhat overkill for the control lines for joysticks and buttons but I can see a purpose for the coin mech. I have heard that there used to be a trick to get free credits in games by zapping the outside of the coin mech with a piezoelectric device such as a gas lighter. I assume they ended up building protection into the coin mechs to stop this working, or destroying the coin mech board and the opto isolator would stop the bolt from affecting or frying the board.

Am just guessing tho.
Title: Re: SEGA System 16 board
Post by: Panther on July 29, 2010, 01:14:46 PM
I have heard that there used to be a trick to get free credits in games by zapping the outside of the coin mech with a piezoelectric device such as a gas lighter.

I can confirm, when I was a young lad (many, many, many years ago before anyone else says anything) that this did work  ;)
Title: Re: SEGA System 16 board
Post by: porchy on July 29, 2010, 04:25:01 PM
it did seem like overkill to me too but these board manufacturers didnt usually waste a penny if they didnt need to.
was a bit frustrated when I couldnt find any info on them but glad i got it sorted and learnt something from it
Title: Re: SEGA System 16 board
Post by: Womble on July 29, 2010, 11:55:17 PM
it did seem like overkill to me too but these board manufacturers didnt usually waste a penny if they didnt need to.
was a bit frustrated when I couldnt find any info on them but glad i got it sorted and learnt something from it

Oh I dunno about that, you can find many bootleg boards that are prime examples of "every expense spared", and Sega hardware is light years away from it in terms of build quality and that all cost money. You can argue that its money well spent, especially if you work out what the increment costs were in terms of coins collected. It would only have needed to collect a few more coins in its life time due to the lack of faults that afflicted cheaper systems for the increased protetion and slight over engineering to be worth it, even if the end operator never saw the correlation.
Title: Re: SEGA System 16 board
Post by: porchy on July 30, 2010, 06:42:21 AM
i often forget that arcade games' main purpose was to bring in the cash
Title: Re: SEGA System 16 board
Post by: AndyT on July 30, 2010, 04:46:17 PM
I have heard that there used to be a trick to get free credits in games by zapping the outside of the coin mech with a piezoelectric device such as a gas lighter.

I can confirm, when I was a young lad (many, many, many years ago before anyone else says anything) that this did work  ;)

It was the guys/girls in the early days of Acorn/CPU that created a electronic based slot machine.