Pac-Man Difficulty Jumper Help Needed!!

farquh

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I want to disconnect a difficulty jumper.

I bought a Pac-Man machine that I was told had the "Atlantic City" chip installed. My game plays at a higher difficulty, but through my research I believe that I have the original chip with a difficulty jumper connected. I believe this is the case, because during my demo mode, the orange ghost captures Pac-Man in the lower left portion of the screen.

First of all - this is the information I followed from another poster - Is this correct?

To see what setup you have watch the demo, if Pac-Man gets caught by:

Inky, lower left = original chip, difficulty jumper not connected
Clyde, lower left = original chip, difficulty jumper connected

Pinky, above ghost box = modified chip, difficulty jumper not connected
Inky, lower right = modified chip, difficulty jumper connected​

If this is correct, then I need to disconnect a jumper – and I've never done such a thing before! Some advice would be great!

Here is a look at my board -

http://i51.tinypic.com/r0nq76.jpg

Here is a look at a chart that I found which tells you where the difficulty jumper is located –

http://i56.tinypic.com/15qp5s5.jpg

So, am I correct in assuming that THIS is the jumper I need to disconnect (circled in red)?

http://i53.tinypic.com/2zhoa4k.jpg

If so, do I need only loosen the solder by heating it? Is there anything else involved?

Finally, can anyone tell me why my board has these two extra chips attached to it? They are stacked right on top of the original board like this –

http://i52.tinypic.com/faotvo.jpg

Can anyone tell me what they are for?
 
Yes desolder the tin bridge.
It's a good idea to use a tin-sucker to remove the old solder because there's a lot of it on there....and it will be hard to remove in another way.

Make sure that nothing makes contact anymore (measure with a DVM).

And get a new camera or learn how to use the macro ! :D
 
Sorry, but what is a DMV?

Yeah, pictures I took last night were really bad! Only have a 4 megapixel camera, and took was too lazy to take the board out of the basement to better lighting conditions. Hopefully you can see what I am asking without too much trouble!

So, to make sure I understand correctly, I've got to desolder the tin bridge - by heating it up, the tin should just loosen, correct? What is a tin-sucker, and what would be the disadvantages if I didn't use one? Can the loose tin be whipped away by another method?

So it is just the tin bridge that is connecting the two jumpers, and the absence of this jumper will instantly make the board operate at it's original settings?

What are those two smaller cards that are stacked vertically on the pcb? Do they have anything at all to do with this?

Sorry for the elementary questions, but this will be my first time attempting any kind of board alteration on my own!

Thanks for the help thus far.
 
Sorry, but what is a DVM?

Digital Volt Meter - also called a Digital Multimeter (DMM).

So, to make sure I understand correctly, I've got to desolder the tin bridge - by heating it up, the tin should just loosen, correct? What is a tin-sucker, and what would be the disadvantages if I didn't use one? Can the loose tin be whipped away by another method?

Google "soldapult" and you will see what he means by "tin-sucker". Solder braid will also work.

So it is just the tin bridge that is connecting the two jumpers, and the absence of this jumper will instantly make the board operate at it's original settings?

Correct. There is also another bridge that can be made to make the game work with alternate character names:

http://lawnmowerman.rotheblog.com/#settings

What are those two smaller cards that are stacked vertically on the pcb? Do they have anything at all to do with this?

One is the V-RAM Addresser and the other is the Z80 Sync Bus Controller. Your board will not run properly without them...
 
Hopefully :) Of course, the green mask will be missing, but as long as the two solder pads are no longer connected, it should be set to easy.
 
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