Having trouble with Banana (Famicom)

[Rimsala]

Hi. I've dumped my collection of 240ish Famicom games, and other than a dozen or so cassettes that are no good and always give me a different CRC when I clean, reconnect and retry, everything in my collection matches known hashes.

However, today I had my first true mystery: I got a cassette of the game Banana, and when I dumped it, I got a wrong CRC... but when I continued to clean, reconnected and retry, I kept getting the SAME wrong CRC. This, in my experience, just doesn't happen. It never happened with all of my faulty cassettes, nor has it happened with CDs that are scratched. But I always get the same CRC with this Banana cassette.

At first, I thought "Hmm, different version?" But then when I used my brain a little more and compared it against the known good dump, I quickly realized that my entire CHR-ROM is blank (FF). I immediately assumed this to be a mapper issue, and since Banana is identified as using mapper #3, I switched to mapper #185. I consistently got a new CRC, but one that still didn't match. I then started going down the list of mappers just trying them one by one, but eventually I gave up since it just felt kinda ridiculous.

Does anyone know if there's any special way to dump this particular cassette? This is the only one in my collection that has done this to me, and it'll bother me if I can't get it to work. I would appreciate the expertise of the No-Intro community! Please help :]

[Hiccup]

Hi. Which dumping tool are you using for this?

[Rimsala]

It's this one.
https://www.ebay.com/itm/273794834847

I believe it comes from here.
https://www.gamebank-web.com/

[Hiccup]

It's this one.
https://www.ebay.com/itm/273794834847

I believe it comes from here.
https://www.gamebank-web.com/

I see. It might be worth (carefully) opening the cart to see what the PCB and chips have written on it.

[Rimsala]

Unfortunately I would have no idea how to do that. I looked into that some years ago, and I think it's pretty unlikely I'd do it without permanently destroying one of the tabs.

Barring that, should I keep trying the mappers? Like I said, I thought "new version" at first, but the more I think about it, the more I think that's just weird. This cassette has the type of back label that would be marked with an A if it was a revision, and there is no A. So if I did open the cassette, what could I find that could help me?

[prominos]

Hi Rimsala,

is this the game you are talking about?

https://nescartdb.com/profile/view/2690/banana

it does seem like you used the correct mapper (#3). I've had this happen before with cartridges with faulty contacts/bad capacitors. I did an experiment, your CHR file for this game should be 16KiB, I created a 16KiB file filled with FFs and it gave me a CRC32 of 690B37D3 is this what you're getting consistently?

It looks like the only additional passive components on this cart are 2 diodes so that rules out the capacitor issue. For me, inserting the cart only slightly in the connector so that it makes contact but is not completely inserted to the bottom of the connector has worked on stubborn games.

Do you have a game with a similar build that you could test with your dumping tool? Ie: A mapper #3 with 1 PRG and 1 CHR ROM chip?

Also do you have an actual famicom console that you could use to test the cartridge? If it can't read correctly from CHR ROM it should be seriously messed up or not start at all.

Unfortunately these famicom games are a pain to open, I have to use a vise to pry the plastic open and its always kinda scary to end up with a broken cartridge (thankfully it never happened!)

[Rimsala]

I got the hash you got, 690b37d3. I tried inserting it not quite all the way down like you said, but I got this same thing.

I do have this cassette.
https://nescartdb.com/profile/view/1497/tetris
It's a mapper #3 with a 32KB PRG and a 16KB CHR (the Rev B). It gave me no problems. I have many other cassettes on the HVC-CNROM PCB as well, and none of those gave me problems either.

I overcame my laziness and hooked my AV Famicom unit up. The game played perfectly. It's a cool game, I like it!

I really can't see why this one mysterious cassette would not work. It plays perfectly, and it connects beautifully. Sometimes, when a game really needs cleaning, it can be hard to remove the game from the dumper/console when you're done. This cassette slides nicely though. It's so puzzling.

[prominos]

That is really weird indeed... the Tetris game even have the same 16KiB size for CHR. The fact that it works correctly on real hardware eliminate the cartridge being faulty. It's as if your CHR act as CHR RAM instead of CHR ROM but that shouldn't be the case. Do you get the correct CRC32 of 9CF17FAB for the PRG file? I'm not familiar with your dumping tool so I am not sure if you get a combined file or a PRG+CHR file. If you do get the correct CRC32 for PRG then I'm afraid I am out of troubleshooting option and the only way to know what is going on for sure would be to open the cartridge and check the chips.

[nnssxx]

Hello,

Try using this little tool: https://workupload.com/file/Munt5q7vNxQ

Unzip the files somewhere, launch nnd.exe and type "do banana.lua", then "q" to exit.

(ignore the CRCs on this image, I used a different cart)

You should get a "Banana (Japan).nes" file, let me know if that dump is good.

[Rimsala]

I know it's been a month, but I checked on this again to find your post. Thank you for replying. Unfortunately, I used your tool and got the exact same CRC I always get, which is 7ba79c4b. Again, the CHR is all FFs.

Since I don't want to attempt to open the cassette, I'm considering just buying another one at this point. If I buy one and it works, maybe I'll open this one for the sake of curiosity.