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Main => Main Forum => Topic started by: Minwah on November 10, 2004, 06:57:36 am

Title: Light-responsive Galaga!
Post by: Minwah on November 10, 2004, 06:57:36 am
I had the lid open on my Galaga cocktail last night, and was taking a few pictures (I might be ebaying it :'( )...

I took a photo and all of a sudden the machine went mad, making the coin-up sound constantly, and giving me loads (FF) of credits.  Damn it's gone wrong I thought...so I turned off and back on, and it was fine again.  Then I took another photo and exactly the same thing happened, so either the flash or camera has this effect for some reason.  I can consistently get this to happen, it is not just co-incidence.

I tried playing the game (with my free credits!) but the game is slightly messed up (I couldn't fire).  It works fine when I put credits in normally.

I just thought it pretty wierd, I can't think of why anything in the machine would react to light (which is what seems to be happening).

 :)
Title: Re:Light-responsive Galaga!
Post by: paigeoliver on November 10, 2004, 07:28:43 am
The gas pedal on a Turbo won't work if sunlight is shining inside the cabinet!

Have any eproms with the windows uncovered? It doesn't make any sense, but that is the only thing I can think of.
Title: Re:Light-responsive Galaga!
Post by: whammoed on November 10, 2004, 08:31:01 am
Perhaps you forgot to give it the customary warning of:"Say Cheese" first?
Maybe someone else has a similar cab they can test this on...wonder if its your machine or all galaga cockatails?
Title: Re:Light-responsive Galaga!
Post by: RayB on November 10, 2004, 09:29:47 am
Speaking of EPROM covers Paige, is it "unsafe" if some are missing? Will the data slowly get corrupted?
Title: Re:Light-responsive Galaga!
Post by: Minwah on November 10, 2004, 10:53:31 am
Have any eproms with the windows uncovered? It doesn't make any sense, but that is the only thing I can think of.

Not sure exactly (I know what eproms are I think but what are their 'windows'?)

I can post one of the very pictures later which would show where the light it hitting.  One thing I didn't mention is that the machine has some kindof extra coin handling stuff - 10p coins give 1 credit, and 50p coins give 6 credits.  Not sure if it is related...
Title: Re:Light-responsive Galaga!
Post by: paigeoliver on November 10, 2004, 11:48:07 am
Yes, Minwah, it is VERY related.

That extra coin handling jobber sends pulses to the PCB, you are making it pulse like a madman with the camera.
Title: Re:Light-responsive Galaga!
Post by: patrickl on November 10, 2004, 12:15:21 pm
I once had a mouse that wouldn't work in sunlight and another that wouldn't work in the dark. That was in the days when mice still used slotted wheels though.

Is the coin handling "stuff" somehow optical? But then I still don't see how you mess up the game itself.
Title: Re:Light-responsive Galaga!
Post by: Apollo on November 10, 2004, 02:17:54 pm
eprom "windows" are for eproms that are UV erasable ( pretty uncommon on any game PCB's ). There is usually a small "window" on the top surface of the chip. You use a special light to erase the eprom ( or you can leave it in the sun for 10 weeks, lol ).
Title: Re:Light-responsive Galaga!
Post by: Zakk on November 10, 2004, 02:29:29 pm
"The dank! The dank!  You can't get rid of the dank!" /carl.

Just sounds to me like you startled the poor thing.  Put it back in a dark room and feed it a few quarters.  It should be just like new in no time.  However, do it again and I'll call the SPCA on you! (Society to Prevent Cruelty to Arcades!)
Title: Re:Light-responsive Galaga!
Post by: DYNAGOD on November 10, 2004, 02:49:04 pm
so all i need is a small flexible shaft and a strobe tube and i can get free credits at the arcade,Wohoo!!,
uh,
no wait,
there are no arcades...  
nevermind........ :(


learn something new everyday  :P



Title: Re:Light-responsive Galaga!
Post by: Minwah on November 10, 2004, 03:15:23 pm
Yes, Minwah, it is VERY related.

That extra coin handling jobber sends pulses to the PCB, you are making it pulse like a madman with the camera.

Makes sense...except why does it keep on going mad or acting wierd after the flash?  Could it be that so many credits are going it at once that it messes up the game?

Either way it's still wierd why the camera interferes with the 'pulsing' of the coin thingy.  I'll have a closer look at it to see if I can tell how it works...
Title: Re:Light-responsive Galaga!
Post by: DYNAGOD on November 11, 2004, 08:40:22 am
with the introduction of red eye reduction technology and other innovations a flash is no longer a simple single flash.
its a complex orchestra of many frames of light and wavelenghts.
that single flash may contain 100 impulses of light.
Title: Re:Light-responsive Galaga!
Post by: Minwah on November 11, 2004, 04:55:24 pm
with the introduction of red eye reduction technology and other innovations a flash is no longer a simple single flash.
its a complex orchestra of many frames of light and wavelenghts.
that single flash may contain 100 impulses of light.

Wow!

I still think it's wierd that light (no matter how much/many/whatever) can interfere with something like this.  I can understand the 'mouse' example that patrickl mentioned, because mice require light to work...
Title: Re:Light-responsive Galaga!
Post by: Thenasty on November 11, 2004, 05:35:35 pm
all you need to do now is to find the machine in an arcade and take a picture  :D