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Disabling Game in Konami SCC Cartridges

If you insert a Konami SCC cartridge into your computer, you can't use the SCC because the game executes. There are different methods to solve this problem. Most involve modifying the hardware. I'll list them from best to worst.

1) Insert after startup

You can of course insert the cartridge when your computer is on (after the BEEP) but this can cause damage to your computer and worse, to your Konami cartridge!

But I think this danger is overrated. I very often insert cartridges into my computer. As long as you do it fast and straight, there is little chance for damage.

2) Piece of Cello Tape

The game can be disabled by covering a pin of the connector with a piece of cello tape. The cartridge no longer operates in page 1 where the AB code normally exists, so the game does not execute but the SCC can still be used (because that's in page 2).

The pin is address line 14 (A14). That's pin 25. Pin 25 is rather annoying to locate, but if you follow this procedure it should be easy. Hold the cartridge such that you are looking at the cartridge connector and the sticker is pointing down. Now, the most left pin is 1, and the most right pin is 49. Count from either left or right to 25, by steps of 2. (49, 47, 45, etc.)

Since A14 is covered, it always seems reset for the SCC/Mapper IC. Page 1 now seems like page 0 for the SCC/Mapper and page 3 like page 2. Normally, page 0 reads like page 2 and page 3 like page 1. So now all pages read like page 2, which doesn't have the 'AB' code by default. Note that the mappers at 5000h and 7000h no longer work, but can't image any program relying on that.

3) Disabling Chip Select

This method involves modifying your cartridge. You need to open your cartridge, cut a line and optionally make a switch for enabling the the ROM.

Since the CS is disabled, the ROM doesn't respond to read requests. Now the game won't work but the SCC will.

First, open your cartridge. It is difficult to do this with the minimum amount of damage, because there are no screws used in the construction of the cartridge. It's closed using "click" notches. There are six of these things. One at each side of the cartridge connector, two at the opposite side (the top of the cartridge) and one at the left and right side.

The following procedure is from the ESE-SCC documentation. So it's © K. Tsujikawa.

  1. Peel of the sticker at the bottom left and right. At both sides, you will find a square hole.
  2. Insert a screwdrive in one of the holes, and loosen the notch which is located at the bottom. Try to open the cartridge a little.
  3. Insert another screwdriver in the gap you have made.
  4. Follow the same procedure for the other hole.
  5. Force the thing open.

Now you can view the innards of your Konami.. The largest IC is the SCC/Mapper chip. The smaller one is the ROM (it has the RC code printed on it), and the long flat thing is the D/A converter (resistor array).

Now, to disable the ROM chip, you must:

  1. Find the CS line from the SCC/Mapper to the ROM. It's easy to locate because there is a condensor connected to it. It runs from pin 8 on the SCC/Mapper to the ROM, pin number:
    If it is a 1MBit ROM (28 pins IC), the CS pin is 20.
    If it is a 2MBit ROM (32 pins IC, Nemesis 3 and Space Manbow), the CS pin is 24.
    If it is a 4MBit ROM (Solid Snake), figure it out yourself because I don't know it.
  2. Cut the line between the condensor and the ROM.
  3. Now, this is important because it is often forgotten: connect the CS of the ROM with resistor (3.3K - 10K) to the +5V
  4. Optionally, you can make a switch over the cut line. In this case you can still play the game. You must make a hole in the cartridge box and cut a piece of the board to make space for the cartridge.

4) Cut Slot Select

This method is easier than 3) but it isn't as good, as you always need a switch to enable the SCC chip. You must cut the Slot Select signal and make a switch over the line so the entire cartridge can be disabled (including the SCC).

Follow these steps:

  1. You must open your cartridge. See 3) for the steps.
  2. Cut the Slot Select line. It runs from pin 4 of the connector to pin 10 of the SCC/Mapper
  3. Connect the Slot Select signal of the SCC/Mapper to the +5V using a 3.3K - 10K resistor.
  4. Make a switch over the cut line. Now you must make a hole in the cartridge box to fit the switch in, and you must cut a piece of the board to make space for it.

5) Remove ROM IC

This method is for the braindead people out there. =)

If you open the cartridge and remove the ROM IC (just cut all the legs one by one) you won't have any problem any more with the game..

BiFi <bifi@msxnet.org>