Final Fantasy J famicom cart

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sleepy9090
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Final Fantasy J famicom cart

Post by sleepy9090 » Mon Dec 13, 2010 7:15 am

Hi everyone,

I recently got a hold of a Japanese Final Fantasy Cart but can't get it to work. I pulled it apart and starting checking it out. Battery was dead so replaced it, used an ohm meter and checked traces and found one that looks intentionally cut.

The cut line goes to CHR A16 (r) on the MMC1A chip. Does anyone know why it is cut and if I should reconnect it?

I guess it's worth a shot, I think the cart is a goner anyway as it appears to have had some sort of water damage from something spilling on it at some point.

I can't find pics of the board online to reference if anyone has one that would be great. Other info on the board it has 3 chips:
SQF-FF-0 PRG LH532210 8749 D (this is PRG chip)
NEC JAPAN 64S20 8747M5 (not sure CHR/RAM?)
SONY 7J57 CXK5864PN-15LL. JAPAN (not sure CHR/RAM?)
NINTENDO MMC1A S 8749 A (this is mapper chip)

tepples
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Post by tepples » Mon Dec 13, 2010 10:45 am

The cut line goes to CHR A16 (r) on the MMC1A chip. Does anyone know why it is cut and if I should reconnect it?
CHR A16 on an SNROM board is an extra chip enable for the PRG RAM, used as an early save-protection method before later MMC1 revisions included this feature in the PRG bank register. Does FF1 ever change this value?

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Bregalad
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Post by Bregalad » Mon Dec 13, 2010 2:40 pm

Well it's weird that a line would be cut ! FF1 just writes $00 to Reg 1 and Reg 2 at startup and never touches this ever again (like most CHR-RAM MMC1 games in fact). This would "normally" lead the SRAM to being disabled (?) at powerup and then enabled by the program.

If the line is cut, I guess a CMOS floating signal is usually interpreted as a logical '1' which means the SRAM is always... disabled. So that would lead to a non-working cart.
Useless, lumbering half-wits don't scare us.

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chykn
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Post by chykn » Tue Dec 14, 2010 7:37 am

Tie pin 20 on the SRAM chip to GND and try it again. Connecting it back to CHR A16 should work as well. If neither of these work, I'd say the board is toast unless you happen to find any more cut traces.

sleepy9090
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Post by sleepy9090 » Thu Dec 16, 2010 2:25 pm

Well I reconnected the line and still nothing. Can't find anymore bad traces but board is prolly junk. Will mess with it some more later. Thanks

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