Playing Solar Wars on a real NES.

This page shows you how to transfer Solar Wars onto an NES cartridge and play it on a real NES. Unfortunately, this takes a bit of soldering skill and patience, so not everybody will be able to do it. This procedure could also involve a large amount of stabbing, sawing, gouging, and burning, so you do all this at your own risk and responsibility. Anyway, for those that are technically inclined, read on...

I'd like to Thank Matthew Conte (itsbroke@classicgaming.com) for coming up (together with Loopy) with this method of making a devkit. A lot of the ideas below are Matt's. Be sure to read the entire document over before even beginning to do anything.

Solar Wars uses a VROM switch to switch the character graphics during the game. The NES' CNROM board has such a VROM switch and Solar Wars works perfectly on this board with the modifications below. So first, you will have to find a CNROM NES game, like Gradius, Cybernoid, Kung Fu Heroes, Mickey Mousecapade, etc... If you are familiar with game ROMs, any cartridge version of a "Mapper 3" game should work as a surrogate for Solar Wars. Once you have the right cartridge, open the cartridge casing. I don't care how; I smashed mine open, for instance. You can find a screw bit that fits the type of the NES' cartridge security screws at MCM electronics (somewhere on the Web). One thing that I found years ago that worked was using a very strong sewing needle or thumbtack on one of the notches of the security screw, and just slowly unscrewing the screw by that one notch. That hurts the fingers after a while, though. Once you have opened the cartridge, noting not to damage the PCB inside, the task is yours to remove the PRG and CHR roms currently on the board. Good luck!

Steps:

1. Desolder the PRG/CHR roms. The pins might be hard to desolder because they extend so far from the blobs of solder, so you might want to do a couple of things: bend the pin tips that extend past the solder back and forth repeatedly until they all snap off. Then you could either use a desoldering braid or sucker to remove the solder from all of the pins, or (failing that,) cut, saw, or file off all the pins from where they extend from the ceramic ROM casing. This will leave you with a bunch of legs sticking into the PCB. Now you can heat the solder for each pin from the underside of the PCB and then quickly slam the PCB down on a hard surface. This will send the leg and heated solder flying from the PCB and should provide you with a clean pinhole into which to stick a socket. Watch your eyes, though. Repeat this for each pin, one after another, not all at once. Repeat for both the PRG and CHR ROMs.

2. Get four short (about 1.25") shielded wires and solder each into the underside of the cart's PCB at pinholes 1 and 27. Just to make sure that you know what you are doing, remember that all chips have a notch on one elongated side, or a circle in one of the corners. Pin 1 is the pin closest to the circle/notch, and the pins are counted counterclockwise from there. (Note that you are NOT to solder wires into pinhole 28! Pinhole 27 is the correct one.) Do this for both the PRG and CHR ROM holes. Make sure the wires do not stick up past the top surface of the PCB; they need to go just far enough to be soldered securely in.

3. Get two 28-pin IC sockets, and bend pins 1 and 27 for each socket upward, so that they will not contact the PCB.

4. Lower the sockets into the PCB and solder them in (except for pins 1 and 27 on each.) Next, solder the wire from hole 1 of the PCB to pin 27 of the socket, and the wire from hole 27 of the PCB to pin 1 of the socket. Do this for both the PRG and CHR sockets. You might want to put some electrician's tape below the bent-up pins so that they are ensured not to contact the board.

   .

5. Find the blob of solder that covers either the H or V mirroring contact points on the board. On the CNROM board, it is right next to the writing that says "NES-CNROM". The blob of solder should be on the contact point marked "H". If it is on the point marked "V", then remove all the solder from the contact point and cover the "H" contact point with solder. If you want to, you could otherwise connect an SPDT switch between these two contact points so that you can switch between horizontal and vertical mirroring.

   Once you have done all this, the CNROM board should look something like this (ignore the scuffmarks on the connector made from an electric grindstone):
   

   

6. Now you will need to find EEPROMs and an EEPROM programmer to program Solar Wars onto the EEPROMs. I got mine from LTDI, but they don't sell them anymore. Try Jameco or somebody else for a cheap EEPROM programmer. Make sure you get two 28C256 EEPROMs for both the CHR and the PRG ROMs. This is the hardest step to do, because of the time and expense involved. I will program the EEPROMs for people if they send them to me (or, again, send me large sums of money to buy the EEPROMs), which means that you don't have to spend $50 just to play Solar Wars.

7. To copy Solar Wars onto the EEPROMs, download the latest version of Solar Wars from my website, and remove the 16 byte iNES ROM header from the .NES file. The lower 32k of the ROM you should then remove and save separately as the .PRG file. The remaining upper 32k of the ROM you should save as the .CHR file. Using the EEPROM programmer, copy the PRG data into an EEPROM and place the ROM in the PRG socket; do the same thing with the CHR data into the CHR socket. Test the cartridge out in an NES or Famicom, and it should (fingers crossed) work!

   If you're having problems understanding what to do with the files, here are the PRG and CHR files directly. Now bone up on your hex editing skills!

8. If the cartridge casing from your game survived the extraction of the PCB, then you can cut some holes in the front of the casing (using a saw or file or hot knife or...) to make room for the EEPROMs. You will probably have to remove the metal bar on your NES which covers the top of the cartridge bay, as this bar will probably block the insertion of the cartridge due to the protruding EEPROMs. The final product should now look like this (I put the board into a mangled SMB cartridge):
   

9. Enjoy your copy of Solar Wars! I should point out that you are still bound by the copyright rules that I outlined in the documentation for Solar Wars, but you're free to use it for your own (and a friend's) personal enjoyment. You are also now able to use the cartridge you just made to try out my NES demos on a real NES.