Re: Switcher for Sega G80 games

The Sega reset circuit may not be the same as TRON. The reason I say
this is I've been working on getting a Sega Carnival PCB wired to Jamma
and it uses the 3vac reset circuit. So I constructed the TRON reset
line and it did not work (don't know why, didn't look into it).

What I did find looking at the schematic was the outcome of the Sega
valid power circuit was one signal became high, so I tied that line to
the 5v rail permanently and it worked beautifully. Think it was a
74LS08 input.

Not sure whether the Sega vectors used the exact same valid power
circuit (never seen one), but with the 3vac... it sure sounds like it.

I can dig up the info and compare it to the G80 schematics after
christmas if you wish.

Cheers
MacMan

On Tuesday, December 24, 2002, at 06:39 AM, Mark E Davidson wrote:

> Ok,
> I have started a batch of Sega G80 projects I have been putting off
> and now have a question.
> I need to put a switcher in my Star Trek. The amp part of the board is
> distorting horribly, 1/2 the frame that held the PS together is
> missing so the supply sits unmounted in the back of the game. The PS
> board is pretty hacked up form inexperience repairs and every thing I
> have read says that it is a good idea anyway.
>
> I have a great switcher i have made as my "standard" replacement for
> all games new or old, that has all the correct positive and negative
> voltages with more then enough amps. This supply also has a Power good
> line out as well. I do NOT want to maintain the original supply for
> that crappie 3v AC for the reset!
>
> All this being said.. What is the Power good signal in a standard
> switcher? Is there a standard of what power good outputs are on
> switches? can I use it for my reset line?
>
> I reasoning behind my thinking is based on a Tron I once had. The MCR
> board series also needs a reset line and has caused many people
> problems installing switcher. When I added a computer PS to my Tron I
> used the supplies Power good line and hooked it to the reset line on
> the game board and never had any problem with it. can I do the same
> here? Any other (easier) ways to switherisize a G80 machine?
> Mr. Jenison.. Chime in any time :-)
>
>
> -=Mark=-
>
>
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Received on Tue Dec 24 10:49:37 2002