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Adding Battery Holder to TSROM Board

Posted: Fri Dec 02, 2011 12:49 pm
by davefmurray
Any tuts, tips anywhere?

The wiki shows a a diff board -

Posted: Fri Dec 02, 2011 2:10 pm
by 3gengames
Board is irrelevant though, follow those instructions.

Posted: Fri Dec 02, 2011 4:41 pm
by BootGod
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.

Posted: Fri Dec 02, 2011 5:59 pm
by marvelus10

Posted: Sat Dec 03, 2011 2:07 pm
by infiniteneslives

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...

Posted: Mon Dec 05, 2011 7:07 am
by davefmurray
Awesome! Thanks for the replies!

Posted: Tue Apr 24, 2012 10:10 pm
by marvelus10
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?

Posted: Wed Apr 25, 2012 12:02 am
by infiniteneslives
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.

Posted: Wed Apr 25, 2012 2:09 am
by TmEE
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.

Posted: Wed Apr 25, 2012 10:37 am
by marvelus10
Ok thank you, Ill wire it up properly then.

Re: Adding Battery Holder to TSROM Board

Posted: Mon Apr 24, 2017 7:55 am
by SnakeGrunger
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 :


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

Re: Adding Battery Holder to TSROM Board

Posted: Thu Apr 27, 2017 8:36 pm
by UncleLudwig
SnakeGrunger how much cost the battery pcb? (sorry for the bad english)

Re: Adding Battery Holder to TSROM Board

Posted: Tue May 09, 2017 8:11 pm
by SnakeGrunger
I can ship one battery board anywhere in north america for 10$US, 15$US for two.
For more just send me a PM!