NES cartridge battery replacement woes

[HunterZ]

So I pulled Crystalis off the shelf a week or two ago and played it for a couple hours, then saved my game and turned off the NES. When I came back the next day, booted up the game and hit Continue, I found that my save data had been lost I did some testing and found that the game retains the save data if I just reset the console, but if I power off it gets lost (even if I'm diligent and hold down the reset button while powering off).

Earlier this week I got a fresh CR2032 battery (the kind in the cart), and the other day I finally got around to replacing the dead one (0.3V remaining of 3.2v or whatever it is that a fully charged CR2032 starts at). Unfortunately, the game still wouldn't keep my save data!

I tested and made sure that the battery was supplying power to the contacts on the board (since I had cut off the old battery and soldered on some wires to a battery holder salvaged from an old PC motherboard) and it was. I changed out the 2 non-ceramic capacitors nearby in case they had dried up (they didn't look bad but you never know). No luck. I even tried reversing the polarity on the battery just in case I had screwed that up, but that didn't make any difference either.

Any idea what's wrong? I don't see any signs of damage on the board, and it did work a couple years ago when I last played it. The only thing I can think of at this point is maybe the SRAM chip was damaged by heat when I was trying to remove the solder around the battery clips; is this likely? If so, would it be a good and/or workable idea to try to replace the SRAM chip with one from, say, Dragon Warrior (I have 3-4 copies of that, so parting one out is an option)?

[Memblers]

Use a voltmeter with black on the battery +, and red on the VCC pin of the SRAM (when it's off, of course). It should show a very low number. Check ground on the SRAM chip and battery this way too (sounds like it is hooked up though).

I guess it's also possible the MMC3 could have failed, but I wouldn't think so.

[HunterZ]

Where can I get the pinouts for the SRAM chip?

I also doubt the MMC3B is bad because the game seems to run fine other than the save functionality.

Thanks.

[Memblers]

I was thinking the MMC3 included a battery-monitor/switching circuit, but I was wrong (I guess the MMC5 and MMC6 do). So it can't be that.

For a pinout of the SRAM, look up a 6264 pinout. But like most DIP ICs, VCC and GND are on opposite corners. In this case, GND is pin 14 and VCC is pin 28.

[tepples]

As I understand it, the Reset+Power trick was to work around the lack of a proper battery monitor circuit.

[HunterZ]

Okay so I'm a TOTAL idiot. I was trying out NES emulators on my new HTPC(*) and I noticed that Crystalis has a hard-to-find save/load menu that I had forgotten about. When testing my real cart previously, I was mistakenly trying to "save" by resting at the inn (that method seemed to actually work across resets but not power cycles, I think because the game may have been autosaving to the NES RAM or something).

At any rate, I reassembled my real Crystalis cartridge just now and tested it out and it works fine Now it's got a new battery and some new capacitors, so it should last another 20 years lol. Probably for the best since the original battery was down to under 0.3V or so anyways (~10% of full voltage).


* - anyone have recommendations for NES emus under Win7? FCEUX and Nestopia have slightly stuttery/skippy sound, and RockNES has a horrible GUI. JNES seems fairly decent, but the emulation isn't as accurate (I noticed some jittering in parts of Crystalis that isn't present in most newer NES emus or on a real NES). SNES9x and Fusion (Kega) run buttery smooth my HTPC, so the stuttering sound of NES emus is driving me nuts

[Xious]

Yeah, it has one of those horrible Hydlide-ish menus, like a lot of RPG ports from Japanese computers. Another example of brilliant UI design... I think you can save at any point in the game though, as I recall, rather than having to be at an Inn, so that is handy. Most computer RPGs let you save anywhere you wanted, and if you needed to revert, you could load your game and bang! be back at the exact spot that you saved.

The 'speak with the King' concept was used in 'Dragon Quest' to minimalize the amount of data space needed to retain save data, as it only saved your equipment and stats. This then became the norm, and most Eastern RPGs used it. It's also why some games have short and sweet passwords, and other have long and hideously long and cryptic passowrds. The less data you vae to retain, the shorter the password and the fewer characters, which are nothing but memory registers.

Take 'Roger Rabbit (FDS) / Bugs Bunny's Crazy Castle': The password is only for the level number, and is four letters long. 'Akumajou Densetsu/CV3' uses four symbols (or was it five) in a 4x4 grid, which is also short and simple, as it assigns characters, level area, and such. Then compare it to a password-based RPG, which can be 20+ alpha-numeric+symbol+lowercase characters long, or an action game that has to track your exact position on a map, or in a level, your equipment, your ammo, characters unlocked, etc.

If that was the case, you'd save time by never turning the system off at all... This is why good games used saving, and cheap games use passwords: Imagin entering a password for 'Dragon Quest III'. It may as well be in hiragana at that point and you'd be there all day...hmm..

That reminds me of 'Wai Wai World' and that insane password system where you have to use the up and down arrows to select each symbol. Or at least a character box where you can quickly enter the code. Not 'press up' 22 times, then down 11, then up 3, and so on for fourteen symbols! That really sucks...

Couldn't Konami put a save feature in there like they did in 'Akumajou Densetsu'? I guess that's be too convenient.

-Xious

Okay so I'm a TOTAL idiot. I was trying out NES emulators on my new HTPC(*) and I noticed that Crystalis has a hard-to-find save/load menu that I had forgotten about. When testing my real cart previously, I was mistakenly trying to "save" by resting at the inn (that method seemed to actually work across resets but not power cycles, I think because the game may have been autosaving to the NES RAM or something).

At any rate, I reassembled my real Crystalis cartridge just now and tested it out and it works fine Now it's got a new battery and some new capacitors, so it should last another 20 years lol. Probably for the best since the original battery was down to under 0.3V or so anyways (~10% of full voltage).


* - anyone have recommendations for NES emus under Win7? FCEUX and Nestopia have slightly stuttery/skippy sound, and RockNES has a horrible GUI. JNES seems fairly decent, but the emulation isn't as accurate (I noticed some jittering in parts of Crystalis that isn't present in most newer NES emus or on a real NES). SNES9x and Fusion (Kega) run buttery smooth my HTPC, so the stuttering sound of NES emus is driving me nuts

[Dwedit]

Worst password ever: Japanese Maniac Mansion.
66 possible characters (Hiragana and A-T), and 104 characters long!

Runner up: Golden Sun save transfer password, it might be longer, but you only enter it once.

Most forgiving password system ever: Who Framed Roger Rabbit, since its password system is utterly broken. It loads the data from the password, checks if it's valid, rejects the password, then does not clear the ram before you start a new game, so it's as if it accepts any password.

Runner up: The Magic of Scheherazade. If your password is incorrect, it will use only the World Selection portion of the password.

[tepples]

This is why good games used saving, and cheap games use passwords

Parents buy cheap games. If the shop is selling one Game Pak for $10 more than another (this was 1989 dollars, mind you), which one will the parent buy? Case in point: NES-TNROM don exits, and I assume that this is because no publisher could afford the prices that NOA would charge for CHR RAM, PRG RAM, and MMC3 mapper.