Adding Battery Holder to TSROM Board

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davefmurray
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Adding Battery Holder to TSROM Board

Post by davefmurray » Fri Dec 02, 2011 12:49 pm

Any tuts, tips anywhere?

The wiki shows a a diff board - http://wiki.nesdev.com/w/index.php/Battery_holder

3gengames
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Post by 3gengames » Fri Dec 02, 2011 2:10 pm

Board is irrelevant though, follow those instructions.

BootGod
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Post by BootGod » Fri Dec 02, 2011 4:41 pm

Actually that wiki page only seems to cover adding a holder to boards that were designed for batteries to begin with, which TSROM is not. I'm pretty sure you need to add some diodes and capacitors as well. I think someone has made a post about modding TSROM in the past.

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marvelus10
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Post by marvelus10 » Fri Dec 02, 2011 5:59 pm


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infiniteneslives
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Post by infiniteneslives » Sat Dec 03, 2011 2:07 pm

Image

This circuit has worked for me and it's what's on SAROM boards. Make sure you use some schottky diodes though, I just used some low drop 100mA ones 568-1617-1-ND from digikey. That C3 in the pic can just be the Cap that's already on your board. Don't forget to put a pull down resistor on the WRAM CE (not to be confused with /CE) A 10K from CE to gnd is all you need.

Oh and nevermind the 100pF for C5 just use 4.7uF or something of the likes and 2n0000 for the diodes (see digikey part # above). This was a schematic for a PCB so I didn't take the time to put in proper values...

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davefmurray
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Post by davefmurray » Mon Dec 05, 2011 7:07 am

Awesome! Thanks for the replies!

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marvelus10
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Post by marvelus10 » Tue Apr 24, 2012 10:10 pm

How detrimental is it to bend pin 28 on your RAM and connect + of the battery, and - to ground pin 14.

I tired this on a TSROM board tonight it seems to work fine, was wondering if there is any long term effects or not?

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infiniteneslives
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Post by infiniteneslives » Wed Apr 25, 2012 12:02 am

marvelus10 wrote:How detrimental is it to bend pin 28 on your RAM and connect + of the battery, and - to ground pin 14.
There's no detrimental effect I guess in regards to damage, except you'll loose your save pretty quickly. You basically hardwired the WRAM to *ONLY* be powered off the battery. So when you're playing the game the chip's power is ALWAYS coming from the battery. Normally the NES supplies power to the WRAM when the game is running. So you're rapidly discharging the battery and it will only last for maybe 100 hours of game play I'm guessing. I could do the math but it isn't long. It's obviously not a good solution at all. It is okay as a temporary power supply if you're removing the chip from the PCB and you don't want to loose the data I guess. You still have to make sure you're biasing CE and/or /CE properly and I'm guessing you're not. So you're still at high risk of losing your data before the battery even dies...

Long story short: Don't do what you did...

EDIT: It might help to understand why this is exactly. Basically the chip consumes VERY LITTLE power when it's not operating that's why a battery can be used to save data for 20+ years, it only requires a tiny trickle of current to save the data. BUT, when the chip is operating (playing on the NES) the power consumed is 1000's of times larger than when shutdown. The battery can't support this much current for very long. So you're quickly discharging the battery anytime you play.

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TmEE
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Post by TmEE » Wed Apr 25, 2012 2:09 am

Untied !CE etc. lines will kill the saves very quick, all it takes is touching the cart edge or even jsut going near it with your finger to cause a toggle and make it latch whatever noise value there is on the AD bus and thus killing all your data.
I had fair bit of headache around it long ago when I experimented like that.
Drive !CE high and/or CE low and you'll do fine, chip gets write protected and goes into low power retention mode.

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marvelus10
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Post by marvelus10 » Wed Apr 25, 2012 10:37 am

Ok thank you, Ill wire it up properly then.

SnakeGrunger
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Re: Adding Battery Holder to TSROM Board

Post by SnakeGrunger » Mon Apr 24, 2017 7:55 am

Hi guys,

Sorry for bumping a very old thread, but following information in this thread I built a neat small circuit to add a battery.

Here's a Mother repro I did :

Image

If any of you would like a copy I have a few extra to sell !

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UncleLudwig
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Re: Adding Battery Holder to TSROM Board

Post by UncleLudwig » Thu Apr 27, 2017 8:36 pm

SnakeGrunger how much cost the battery pcb? (sorry for the bad english)

SnakeGrunger
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Re: Adding Battery Holder to TSROM Board

Post by SnakeGrunger » Tue May 09, 2017 8:11 pm

I can ship one battery board anywhere in north america for 10$US, 15$US for two.
For more just send me a PM!

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