Scrolling issue on pirate cart, fixable?

[SkinnyV]

Hey guys, I was wondering if anyone could help me figure out and fix a pirate nintendo cart I have. It used to work great a few year ago and I have recently listed it on ebay after doing minimal testing. I tried it in an old nes and it booted right away and didn't really do any further test. Now I figured I would play a game or two before packing it to ship and found out that it has a weird scrolling issue. I have contacted the buyer and he is willing to wait a bit and see before canceling the transaction.

After opening it up (and wondering how it ever worked in the first place with that kind of solder job:)), I redid a few solder joint as there was gaping hole without solder around the chip legs connection but still no go. Only thing I could think of is those capacitor that look like they were added halfway during manufacturing and soldered by monkey.

What do you guys think?

Here some pictures of the board:

http://www.skinnyv.com/Cart/

And here's a video of the scrolling issue I am referring to:

http://www.youtube.com/watch?v=_lFj5DJlcOY

It's not only because I want to sell it but also because I would be sad to see this cart thrown out as it was pretty hard to find in the first place.

Thanks for your help![/code]

[tokumaru]

http://www.youtube.com/watch?v=_lFj5DJlcOY

It's a mirroring issue. If you open the game in FCEUX, open the name table viewer, and change the mirroring from "vertical" to "horizontal" or "single screen" as soon as the level starts, you get the exact same behavior as shown in this video.

Why this happens is beyond me, specially considering that the game used to work. I would start by checking what's being fed to the CIRAM A10 line (pin 18 on a Famicom cart, 22 on a NES cart), which is the line that controls mirroring. This game uses a mapper with mirroring control, so logically there should be a connection from the mapper chip to this pin. Check that connection carefully to see if there's anything wrong with it.

[Banshaku]

Tokumaru beats me to it. Mirroring issue.

[SkinnyV]

Thanks for the head up guy, I'm trying to look carefully at these line but for now not much was found except that there is a possibility that it goes to one of those chip with capacitor soldered to. How likely is it for a capacitor to stop working or be defect? Those are labeled 471 on the cart PCB, I have pulled out very similar capacitor from an old piece of electronic to try to replace them but they're listed as 47 but look exactly the same, I don't supposed I could replace them with those right?

[tokumaru]

Resistors and capacitors are beyond my level of knowledge. As a programmer, I can only understand basic digital electronics, which means I understand the functions of the ICs and why they are wired together the way they are, but I have no idea what capacitors and resistors are for and why the ICs can't do the job by themselves.

The only thing I can tell is that there's something corrupting the CIRAM A10 line. Hopefully someone with better understanding of electronics will be able to help you.

[socram8888]

471 = 47x10^1 = 470nf capacitor

These are ceramic capacitor. These usually don't break, so don't ever try to replace it

[SkinnyV]

I appreciate the help guys but seem I'm at a loss... I'll keep looking at the board, i just don't understand what triggered this issue as it was mainly in a closet for the past 7 years and i remember playing with it when i found it at a pawn shop as a young nes collector:)

Could it be something on the integrated 60 to 72 pin adapter? There's a few resistors and about 2 three legged black component on it... I doubt there related to the A10 wram/chr line but i was really hoping to find something wrong easily fixable

[socram8888]

These resistors, capacitors and transistor are a CIC stun circuit, used to lock the CIC thus allowing the user to play unlicensed NES/FC games

What game it is?

EDIT: Can you try to remove that resistor on the adaptor?:
http://www.skinnyv.com/Cart/adapterfront.JPG
The leftmost one. That's the only thing strange on the adaptor, as the other components have no connection with the CPU nor the PPU

[SkinnyV]

The game is bio miracle Bokutte upa. I'll try removing the resistor but it used to work with it so unless it is defective which would be surprising for a resistor, I'm not holding my hope's up...

[SkinnyV]

Tried to remove the left-most resistor and it just messed up the CIC stun circuit, the game would boot to the title screen and contently reset until I soldered it back.

I have also just noticed the game is different than the official konami version (never tried the official one before). There is a level selector on the title screen that you control with the Select button and it boot straight to the title screen, no Konami logo or anything. I wonder if this was ever dumped.

[kyuusaku]

471 = 47x10^1 = 470nf capacitor

These are ceramic capacitor. These usually don't break, so don't ever try to replace it

Actually that'd be a 470pF cap, but it definitely isn't the cause of the problem. It's a broken trace to VRAM ("CIRAM") A10.

[SkinnyV]

I'm still fiddling with the cart but so far, no luck. I managed to corrupt all the GFX after redoing some solder connection that seemed to separate from the board trace and the mirroring effect seemed to be gone for one boot while GFX were scrambled but the minute I resetted the nes it came back. I fixed the GFX issue for now but it is hard to see where the a10 line goes since it get lost under the massive number of chip used to simulate the VRC IV mapper.

But the more I played with this cart while trying to fix it, the more interested I became in it as it turn out it is different than the official konami FDS and subsequent cart release. It has the level selector and no difficulty setting and it also include the baby animation near the game title as seen in the FDS rom and not on the cart release. Now I'm trying to find a way to dump the PRG and CHR while trying to fix the mirroring issue. Funny that I had this cart for almost a decade and never really knew about these differences.

Edit: Found some info about it from kevtris, seem it use Mapper 42:

http://kevtris.org/mappers/single_pirat ... acleA.html

I wonder if he ever dumped it...

[kyuusaku]

Post clear pictures and it will be clear which chip it connects to. The signal source will be a multiplexer.

[SkinnyV]

I'll have to find my multimeter, my brother borrowed it and never brought it back:) I'll try to trace the A10 live after that and see finaly what is causing the mirroring issue. It's getting personnal between that cart and me, I just want it fixed lol

[SkinnyV]

I wasn't able to fix the issue yet and it's frustrating. But I'm curious, Kevin Horton's page on the same pirate cart describe the cart as using 128k ROM and 8K Ram. I was wondering how it was working... Does the main rom contain both the PRG and CHR and transfer the CHR data to the ram when you turn on the nes? I thought all nes cart were the same with 1 PRG and 1 CHR chip. Does it mean this cart's CHR is only 8k or does it transfer chunk when needed and refresh? And since I am interested in having this dumped in the future (since it's different than any other version available), let's say I complete the pin out of the rom chip which would be pretty easy (already did about 7 address line), would I be able to just read the content of the chip with a eprom reader and voila or the data would be mixed up because the mapper wouldn't have organized the data? And if i was to try to dump it, what chip profile could i use to read it ? Most 128k rom chip i know are in 32 dip package and not 28. Do you guy know of any supported chip (for a willem reader or the like) that is 128k and 28 pin?