possibly broken 3do part 2

lilmul123 · Post by **lilmul123** » Tue Jul 31, 2007 10:47 pm

After all that hubbub, It wasn't the battery after all. That makes sense because NVRAM isn't supposed to delete everything when the power is turned off. Anyway, my 3do FZ-10 deletes all the saves at power-off. I really want to know what that battery does now. Is the RAM busted? The saves save fine (If I quickly turn off and on the system, the saves are there), but they don't stay if i leave the power off for more than a few seconds. Anyway to remedy this?

bonefish · Post by **bonefish** » Tue Jul 31, 2007 11:15 pm

A quick question, is the polarity correct on the battery, and is it a good battery?

lilmul123 · Post by **lilmul123** » Tue Jul 31, 2007 11:17 pm

According to what it says on the board, they should be. When the battery was on it, that's also the same position it was in. I wanted to try switching it around, but I don't want to risk breaking anything.

edit: Yeah, I bought a brand new battery for it. I checked both with a multimeter and found out later that both are outputting 3 volts. So really, I didn't need to take the battery out of there.

Mobius · Post by **Mobius** » Tue Jul 31, 2007 11:37 pm

It really shouldn't be the NVRAM, since, as you said, it's NVRAM. The whole point is to not lose data when it loses power. So perhaps the NVRAM itself is going bad?

And this leaves me curious as to what the battery does, as well.

lilmul123 · Post by **lilmul123** » Tue Jul 31, 2007 11:44 pm

My friend has a copy of this thing called "Game Guru" and I guess it has some memory options (format, erase etc etc) so I'm going to try running some of these things on it and see what happens.

bonefish · Post by **bonefish** » Tue Jul 31, 2007 11:57 pm

Game Guru, yes, give that a shot. A nice format may do it.

lilmul123 · Post by **lilmul123** » Wed Aug 01, 2007 12:08 am

Same deal. *sigh* I guess I can never turn my 3do off!

lilmul123 · Post by **lilmul123** » Wed Aug 01, 2007 12:25 am

Is there anywhere on here that tells of where the locations of the chips are? I want to know which one is the NVRAM so i can figure something out.

edit: From what I can tell, we've been lied to for many years. I don't think the 3do saves on NVRAM. If it was NVRAM, the saves wouldn't be deleted everytime I shut off my 3do.

If you can see here: http://www.heimcomputer.de/english/kons ... blast.html

The 3do blaster also has a battery on it, and this site says it's 32k of SRAM. I'm guessing MAYBE the FZ1 and the goldstar 3do's are NVRAM, but these are definitely not.

bonefish · Post by **bonefish** » Wed Aug 01, 2007 1:45 am

So... in an effort to lower costs maybe... they went to sram?

Wait. Check for continuity on the battery circuit! On and around it.

lilmul123 · Post by **lilmul123** » Wed Aug 01, 2007 1:56 am

I THINK I've found the problem. If what I'm sticking my multimeter at is the SRAM chip, I think i've found the point where it accepts the 3v power signal. From an old usenet archive, i pulled up an article where a guy tells of how the SRAM chip uses 5V when the 3do is turned on, and 3V when it's turned off. I turned on the 3do, and sure enough, one of the pins IS accepting 5 volts of electricity. The point where it accepts 3V however is only showing slight bursts of .01-.05 v of electricity. If i disconnect the battery, and then touch this point again, it shows .00 v of electricity. My idea now is to simply connect a wire from the + of the battery to this point, but I'd really like to see some kind of schematic of the SRAM or the labeled innards before i start connecting 3 volts of electricity to precious electronic parts that I have educated guesses on.

edit: Also, the - pin for the battery doesn't go anywhere on the board, it's just a ground.

bonefish · Post by **bonefish** » Wed Aug 01, 2007 3:47 am

Jackpot:

http://www.datasheet4u.com/html/C/X/K/C ... n.pdf.html

Sony SRAM CXK58257 Datasheet

Good thing the 3do is mostly off the shelf stuff.

lilmul123 · Post by **lilmul123** » Wed Aug 01, 2007 4:44 am

Excellent! Thank you. Time to get to work.