Earthbound donor board question

I have an Earthbound board with major cracks running through the center. Looks like someone stepped on it. Luckily none of the ICs have apparent damage. My thinking is to swap all of the needed ICs with a donor board. There are a few cheap games to choose from: http://www.snescentral.com/pcbboards.php?chip=SHVC-1J3M-20

My question is, which chips do I need to replace? My guess would be the ROM, and perhaps the SRAM.

Thanks!

 

I would just swap the MASK ROM (U2) and test if it works, maybe SRAM if you really want your old save, but not sure how long it can survive without a battery

 

Since I'm not sure what my FLGS has in stock, I'm looking at earlier revisions of the board and their games. Would it be possible to use SHVC-1J3M-11 in place of the SHVC-1J3M-20? That'll give me two more sports games as options.

 

I'm quite certain it should work just fine with that board too. I have read that since the game has some nasty protection, don't try to get a donor with more than 64k SRAM, as it might trigger it

 

Thanks for the tips! I'm hoping I can get the game tomorrow or else I'll have to wait for ebay. I bought a desoldering station I've been eyeing for a while. With luck I'll have this finished by Sunday!

 

That might be an overkill, I would just use braid for such a simple job. If you have never done it before would be good to practise on something else first.
Good luck and keep us posted!

 

Desoldering station is infinitely better ans faster than using braid for through hole chips

 

Just replace the mask rom with the earthbound chip, btw get a solder sucker and some flux, waaaay better than braid, it takes me less than 10 minutes to do this on a super smash cart.

 

Less than 5 min with braid for me

 

I use braid a lot. But desoldering station is better. Especially on pins where it's connected to a large trace that takes a lot of the heat

 

Good to know, I don't have one but I do have Yihua hot gun rework station, could I use that to desolder?

 

Ive done this job with chipquik. Made it pretty easy and didnt need a station.

 

Update: IT WORKED!!!

I used Madden '95 for a donor board, with PCB SHVC-1J3M-11. I only desoldered the Mask ROM first. When soldering in the Earthbound ROM I noticed that the Madden ROM had two fewer pins and the holes were soldered over on the board. Luckily I caught myself before trying to force it through like some sort of Neanderthal.

Before trying it I checked the voltage on the battery, then shorted it for a minute or two to erase any saved games that might be on the SRAM.

It booted on the first try! I played for a bit and saved my game, then took out the cart and waited a bit. The save game stuck! Not sure if it's worth my time trying out all of the Earthbound copy protection quirks.

I filmed the whole process, from dramatic reveal of a horribly broken board to the moment of triumph. I have one more section to film then I'll edit it and post it here.

 

Was this the cracked one that was on eBay?

 

Good stuff, glad to hear it's working

 

Yes it is. I should message the seller and let them know

The video is up! I hope you find it interesting!

 

If you are going to use Ness as the name, select <I don't care> and you'll get Ness as your first choice

 

I figured that out after I forgot Paula's name. I am not a smart man, and apparently not a true EathBound fan.