SMB2j reproduction, question on batteries

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Beji
Posts: 17
Joined: Mon Jan 06, 2014 4:07 pm

SMB2j reproduction, question on batteries

Post by Beji » Mon Dec 08, 2014 3:13 pm

Hey folks, how's it going?

I recently bought a INL TSROM PCB so I could make a repo of SMB2j. I am planning on using Loopy's version of the game.

I didn't realize it until now, but the game needs a battery for saving how many times you beat the game and gain access to other stages.

How can I go about adding a battery to my TSROM board, and what kind of modifications (if any) will I need to make? I'm not into soldering, never did it, that's why I buy Paul's INL stuff, so when replying to post any information, just assume I'm stupid and overly explain if need be.

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getafixx
Posts: 365
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Location: Canada

Re: SMB2j reproduction, question on batteries

Post by getafixx » Mon Dec 08, 2014 4:26 pm

Add a CR2032 or equivalent battery, wire the negative pin to GND, from the + pin wire a 1N4148 diode, and a 1K resistor in series and run that to the VCC pin on the PRG-RAM. That should be enough to keep the saves intact. The diode is required so that the SRAM doesn't run off the battery when played in the console.

lidnariq
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Location: Seattle

Re: SMB2j reproduction, question on batteries

Post by lidnariq » Mon Dec 08, 2014 4:48 pm

You need to keep the battery from powering the rest of the cartridge, so there should be two diodes.
Looking at the pictures from INL's thread ( e.g. viewtopic.php?p=110539#p110539 ), I bet there's a solder jumper there (Probably "Vbb"/"Vcc") and a place for a part that's two diodes in one (probably the three pads immediately to the left).

Of course, you're probably not up for surface mount soldering if you haven't done any soldering before...

A slightly better picture than the one he's provided would be helpful to be sure that what I said is true.

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