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High Score Save

 Overview

This is a high score save for Time Pilot and Gyruss. Time Pilot was one of my favorite games growing up, and Gyruss is just a fantastic game, so they were the obvious choices (for me) to start the Konami high score save project. So why are these two games together? Simply because the similarities in hardware allowed me to combine the high score saves for them. That's right, one ROM works in both games, and for all known versions (Konami, Centuri, and bootlegs). You just pop the new ROM in the existing extra socket on the board (Konami used this for a "test chip"), replace one RAM chip with a non-volatile RAM, and your scores are saved! The only thing preventing this from being a 30 second upgrade is that the RAM chip you need to replace is unlikely to be socketed. You'll have to remove the RAM and install a socket for the new NVRAM. If you don't have the soldering skills to do this, please find someone who does to do it for you. An experienced tech can do the job in under 10 minutes. You perform these modifications AT YOUR OWN RISK!!!

 How It Works

The first thing these two games do when they boot up is look to see if a test chip is installed, and if so, run that code. So I've taken advantage of this and re-written the boot routines to run in that space. The new routines protect the high score RAM from being initialized and overwritten with defaults. Once the high scores are safe, I jump back to the appropriate place in the original code. No changes are made to the original ROMs. I added the ability to reset the high scores by dipswitch selection. On Gyruss I chose an unused dipswitch, switch 8 on SW3. Time Pilot doesn't have any extra switches so I chose an unlikely combo to do the reset; all SW2 switches ON except for switch 3 (cocktail mode). If the high score table is found to be corrupt (like when you first install the NVRAM) it is automatically reset. Here are what the tables look like when reset:

 Installation

 Time Pilot

The existing program ROMs (2H, 3H, and 4H) are left intact. The new guy is wearing shades. 8)

2) The 2K static RAM at location 9F needs to be replaced with a non-volatile memory. If that chip happens to be socketed (I haven't seen them socketed on legit boards, only bootlegs) then this step will be a breeze; just pop out the RAM and plug in the NVRAM. If not, then you'll have to remove the chip and install a socket. Don't try to save the chip you are removing... 2K SRAM (6116, 2128, etc.) is still very cheap (~$1), so risking damage to your board is foolish. Just snip the legs at the body of the chip, pluck them out one at a time with your soldering iron, clean out the holes using a solder-sucker or soldering wick, and solder in a 24-pin socket. These Konami boards are pretty easy to work on, so you don't have to be a soldering expert to pull this off. Here's what it looks like with the socket installed:

Now you need to plug in your NVRAM. You could use a battery-backed SRAM like the Dallas DS1220 or the ST M48Z02. I've chosen to use a newer technology that doesn't rely on batteries, the Simtek 25C48. It has a 100+ year data retention, so you'll never have to replace it! Here's the board with the Simtek NVRAM installed:

3) This step is optional. You probably noticed the electrolytic capacitor right above the NVRAM. It's probably not needed here, but I added it just to be safe. If the power supply cuts out too fast on power down the NVRAM may not have enough time to complete its autostore operation. Adding this capacitor insures that the chip has time to store your high scores to its non-volatile memory on power down. A 100uF to 220uF cap (rated 16V or higher) works fine for this. I pulled out the 104Z ceramic cap that was above this RAM and put this cap in its place. Make sure you get the polarity right (negative is to the left in this picture).

 Gyruss

1) The new high score save ROM installs in the socket at 14J on the CPU board:

2) The NVRAM goes in location 3J (the RAM in the middle):

3) Optional capacitor. I installed it at the top-right of the RAM at 5J (location is not critical, just put it in the vicinity of the NVRAM).

What about bootleg boards, you ask? There are several different kinds out there, and some may not have the extra ROM socket installed, so you'll have some extra work to do (best thing to do is hack the board to accept a single 27256 EPROM that contains all the program code). RAM is likely to be socketed, so you luck out there. I don't have any bootleg Gyruss boards on hand right now, but I do have a single-board bootleg of Time Pilot (a "Space Pilot" before I reprogrammed it with the Konami ROMs) which I succesfully installed the high score save on. For a crude pic of the board layout that shows the ROM and RAM locations click here.

Kits

one 2764 EPROM programmed with the high score save code

one STK25C48 NVRAM

one 24-pin socket (machine pin if I have them, AMP dual-wipe otherwise)

one 100uF (25V) electrolytic capacitor

Price is $25 each, plus $4 shipping (any number of kits, in the US only, by USPS Priority Mail).

 Download

For the do-it-yourself'er. If you've got your own programmer you can just download this ROM image and burn it to a 2764 EPROM. Please consider offering a donation. Developing and testing these score saves takes a considerable amount of time and resources. If you've got some boards, RAM, EPROMs, etc. that you'd like to donate to the cause, please contact me. And of course, cash is always appreciated!