So, despite what I said in an earlier post, my R.C. Pro Am cart continues to get scrambled. Sometimes it scrambles, sometimes it doesn't. It always happens on a transition, where bankswitching presumably would be occurring. This leads me to believe that the mapper is faulty. I'm considering getting RetroZone's MMC1 repro board and soldering the PRG and CHR rom chips to it in an attempt to preserve this game. Do you think it might work?
It's hard to say, but I highly doubt the MMC1 is the cause of your scrabled graphics. The terrible connector should be at 99,99% what causes you problems. Anyway if the PCB of retro zone make better contact then maybe that will fix the problem. You'd have to be able to disolder both roms without damaging the pins which is very hard to do (I only suceeded once).
i would think it would be easier to just make a new board with flash memory, and use the old case
Bregalad wrote:
It's hard to say, but I highly doubt the MMC1 is the cause of your scrabled graphics. The terrible connector should be at 99,99% what causes you problems. Anyway if the PCB of retro zone make better contact then maybe that will fix the problem. You'd have to be able to disolder both roms without damaging the pins which is very hard to do (I only suceeded once).
It's really not that hard with proper tools and if you know how to do it.
Well, the reason I suspect there's something wrong with the particular cart is *NONE* of my other games have this problem. They all work flawlessly except for this one game (except for Castlevania, which I hear has a bug in the early carts). I have a new 72 pin connector in there which so far is remaining quite snug. Ironically I don't care all that much about R.C. Pro Am so it isn't a huge deal, it's more the observation that if it can happen to one game, it can happen to others, and I want to use it as "practice" as it were for preserving my collection as the years go by and more things wear out and die...haha
RetroZone's MMC1 board is for EPROM and FlashROM. Nintendo Mask ROMs will not work unless you rewire the different pinout to match.
They will work as long as the ROMs are below 128k, there is no funky pinout by Nintendo.
I'm fairly convinced at this point the cart itself is the prob. If connection was a problem, the game should be scrambled on start up and it almost never is. It is always in transitions. The screen blanks out, something else is loaded in CHR and in the nametables, and then the scramble happens. And it is intermittently. I also tried putting some pressure on the cart while it was in the NES to make sure the connection was better.
This particular cart was not mine originally, changed hands a couple of times, and when I found it it had been being stored in rather questionable conditions... thus it seems possible there is something wrong with the chips or the mapper on the cart... oh well I'll probably just get an extra copy eventually or just play from my powerpak. It's just interesting to try to figure out what the problem is..
Well, it's not because scambled graphics don't show up on title screen and show after a transision that the problem is not the connexion. It could be that the glicthes are black on black on title screen, or that only certain tiles are used and so the garbled CHR xx line does not take into account significantly to the graphics.
To me very often a game doesn't work I have to reset a couple of times before it works, and after I've seat confortably in from of the TV after starting a new game I found myself with scrambled graphics so I have to reset a couple more times to get the thing working. (this doesn't happen on emulation so I use that instead)
The ROM chips would be either working 100% or completely fired, the data in it is very very unlikely to get "corrupted" or something like that. The same applies to the MMC1. Maybe the coupling capacitor could be disfonctionning, resulting in some chips behaving incorectly under some rare circonstantces when there is a lot of toggling happening on the bus.
Anyway if you can't repair the cart you could try soldering the ROMs back to a new board, it should work perfectly in theory.
After reading a few other posts on this site, I am beginning to believe I simply destroyed the connectors by cleaning them with an abrasive substance. They have been worn down so they no longer appear gold. I bet that's what's going on. For some reason I have not had this problem with any other cartridge. Maybe this cart had been cleaned several times before and was already worn down a lot, or just had thin connectors.
The gold plating is very thin. Just enough to stop the copper/tin/whatever underneath from oxidizing. I bought a copy of Super Contra, where the connector was almost totally orange. I know we shouldn't have played it like that, but it actually worked (in a toploader, which seems to connect better to everything anyways).
Only solvents I'd recommend for cleaning are Isopropyl Alcohol, and de-ionized, or distilled water (not tap water).