Weird NES cart issue

[nasune]

So, basically I have a copy of Time Lord for the NES that has some weird issues. It has severe background issues (from not loading to rolling backgrounds), while the objects (as well as the player and enemy sprites) themselves are in the proper place (ie collision is where it's supposed to be, I'm just playing the game basically blind). In addition to that, the game pauses itself regularly.
I've already verified that it's not the console by trying it on three different consoles and TVs, plus playing the game via flashcart renders everything normally. Does anyone know what could be wrong with the cart?(Is it the PRG Rom, one of the capacitors, something else?)



Here's a clip of what I mean.

ps.

please ignore the lack of video quality, or audio period. Due to the lack of proper equipment (read, all I had was a cheap EasyCap converter) I had to improvise to get the footage.

 

[nasune]

So, an update to this many a year later, I'm giving up on this. I've replaced the ram and caps, switched the CIC with a known working game, tested the 74hc161 chip (which indeed tested just fine), and even dumped the game only to see that it matches the roms found on the internet. No idea why it doesn't work but I'm done with it (at least for a good long while).

 

[hippy dave]

 

[tech3475]

Did you try cleaning the contacts with a cotton bud and IPA?

The PPU connects directly to the cart.

https://www.nesdev.org/wiki/Cartridge_connector

I presume other original carts are fine?

 

[nasune]

Did you try cleaning the contacts with a cotton bud and IPA?

The PPU connects directly to the cart.

https://www.nesdev.org/wiki/Cartridge_connector

I presume other original carts are fine?

Yep, I cleaned it several times to no effect. It plays every other cart, and the thing that drives me mad is that If I take the dump and play it on a flash cart it works no problem. The only thing I can think of at this point is that there's some weird anti piracy that detects the NES clone as a clone rather than an original NES (the console is a clone, not the cart) which the flashcart bypasses somehow. Although that does beg the question of whether the clone has a CIC chip. I'll have to check that in a little bit.

 

[skawo]

If the ROMs dump fine, and you already replaced all the other components, then I'd say there might be a break in a trace somewhere. Have you tried beeping all the connections out with a multimeter?

 

[tech3475]

Yep, I cleaned it several times to no effect. It plays every other cart, and the thing that drives me mad is that If I take the dump and play it on a flash cart it works no problem. The only thing I can think of at this point is that there's some weird anti piracy that detects the NES clone as a clone rather than an original NES (the console is a clone, not the cart) which the flashcart bypasses somehow. Although that does beg the question of whether the clone has a CIC chip. I'll have to check that in a little bit.

The way the CIC works is that the chip in the console detects the chip on the flash cart and enters a reset loop if the chip fails.

I don't know of the top of my head if there are any games which specificaly check if the 10nes is missing/disabled, if that's even possible to begin with as IIRC the pins go from the cart to the 10NES.

Does the PCB thickness look any different than the other carts?

What clone console are you using?

Is the ROM you're using the one from your original cart.

 

[nasune]

If the ROMs dump fine, and you already replaced all the other components, then I'd say there might be a break in a trace somewhere. Have you tried beeping all the connections out with a multimeter?

Just checked it again since I figured it could be a possibility that I damaged some traced replacing the chips but sadly it all goes where it should.

The way the CIC works is that the chip in the console detects the chip on the flash cart and enters a reset loop if the chip fails.

I don't know of the top of my head if there are any games which specificaly check if the 10nes is missing/disabled, if that's even possible to begin with as IIRC the pins go from the cart to the 10NES.

Does the PCB thickness look any different than the other carts?

What clone console are you using?

Is the ROM you're using the one from your original cart.

The cart itself is normal, and all but the RAM chip (from a Neo Geo MVS board) and the caps are original parts (albeit with the CIC chip swapped with another original game). As for the clone console, i've tried both a NASA HOR-92, and an Entertainment Computer System clone (a quick google search does show that apparently both were made by the same company).
And, yeah, I have never heard of a game doing some specific check either, but all the components appear to be working as they should so I'm kinda out of ideas at this point.
The thing that makes it especially unbelievable though, is that it does work with a flashcart, so if this was a known thing I should be able to find something on the internet (why would it work on a flashcart otherwise).

 

[tech3475]

Just checked it again since I figured it could be a possibility that I damaged some traced replacing the chips but sadly it all goes where it should.

The cart itself is normal, and all but the RAM chip (from a Neo Geo MVS board) and the caps are original parts (albeit with the CIC chip swapped with another original game). As for the clone console, i've tried both a NASA HOR-92, and an Entertainment Computer System clone (a quick google search does show that apparently both were made by the same company).
And, yeah, I have never heard of a game doing some specific check either, but all the components appear to be working as they should so I'm kinda out of ideas at this point.
The thing that makes it especially unbelievable though, is that it does work with a flashcart, so if this was a known thing I should be able to find something on the internet (why would it work on a flashcart otherwise).

This is why I'm curious about the physical condition of the cart compared to others and whether you tried the rom dump on the flash cart, in case there's a version/revision difference.

Did you check the traces on the cart itself?

 

[nasune]

This is why I'm curious about the physical condition of the cart compared to others and whether you tried the rom dump on the flash cart, in case there's a version/revision difference.

Did you check the traces on the cart itself?

The cart looks just like any other cart I suppose, there's nothing weird about it as far as i can see. As far as the traces on the cart, yes I've checked them all. there are three lifted pads but those are inconsequential, since they bridge the wide body old RAM to narrow body type chips (which is the type the new RAM chip is). Other than that everything is just the way it should be. Only thing that may be faulty at this point are the small resistor like caps, so I might change those over to ceramic caps to see if that'll work. That said, measuring them in circuit does suggest they are fine, but you never know.

edit: And the dump works just fine on a flash cart.
edit 2: Just replaced the resistor like caps, and it made no difference.

 

[tech3475]

The cart looks just like any other cart I suppose, there's nothing weird about it as far as i can see. As far as the traces on the cart, yes I've checked them all. there are three lifted pads but those are inconsequential, since they bridge the wide body old RAM to narrow body type chips (which is the type the new RAM chip is). Other than that everything is just the way it should be. Only thing that may be faulty at this point are the small resistor like caps, so I might change those over to ceramic caps to see if that'll work. That said, measuring them in circuit does suggest they are fine, but you never know.

edit: And the dump works just fine on a flash cart.
edit 2: Just replaced the resistor like caps, and it made no difference.

Have you tried reflowing the solder joints?

I know it dumped fine, but I'm wondering if maybe when it's in the console something might be breaking?

Edit: What RAM chip did you use? I know you said NeoGeo MVS, but what's the exact model?

 

[nasune]

Have you tried reflowing the solder joints?

I know it dumped fine, but I'm wondering if maybe when it's in the console something might be breaking?

Edit: What RAM chip did you use? I know you said NeoGeo MVS, but what's the exact model?

Just reflowed the PRG, since that was the only thing left that wasn't replaced to no avail. As for the RAM chip it's a CX5864BSP-10L to replace the KM6264BL-10L, which as far as I can find from the datasheets should work. (8K CMOS high speed static ram with compatible pinout)

 

[DiscostewSM]

Time Lord is a game that utilizes the MMC3 mapper chip, right? That provides some bank switching capabilities as well as scanline-based interrupts. I wonder if that's starting to become faulty.

 

[nasune]

Time Lord is a game that utilizes the MMC3 mapper chip, right? That provides some bank switching capabilities as well as scanline-based interrupts. I wonder if that's starting to become faulty.

Not as far as I'm aware, the only thing that's on there is the 74HC161. No MMC chip at all (wish it had, since I could've swapped that out).

 

[DiscostewSM]

Not as far as I'm aware, the only thing that's on there is the 74HC161. No MMC chip at all (wish it had, since I could've swapped that out).

Okay, Google was saying it used it, but other places said it didn't. I checked over on eBay to find folks selling the game to see if any had it opened up to show the circuit board, and they also showed it did not That just reaffirms to me not to trust AI.

Anyways, this is what it looks like on the inside (for NES-LZ-USA), according to the eBay listing for the game:

https://www.ebay.com/itm/168066459386

Does yours look like that?

 

[nasune]

Okay, Google was saying it used it, but other places said it didn't. I checked over on eBay to find folks selling the game to see if any had it opened up to show the circuit board, and they also showed it did not That just reaffirms to me not to trust AI.

Anyways, this is what it looks like on the inside (for NES-LZ-USA), according to the eBay listing for the game:

https://www.ebay.com/itm/168066459386


View attachment 552937

View attachment 552938

Does yours look like that?

Yep, with the exception being that the CIC chip is the PAL one. (Well, that and all the changed components at this point. It originally looked like that though.)

 

[DiscostewSM]

Well, I dunno what to tell ya. Only thing I can think of is trying to adjust how the cart connects. I know with my frontloader NES, some games just work when inserted. But others won't boot or have corrupted graphics, and that' when inserted and flushed against the back. But when I tilt it slightly while they're locked in, some work fine. Other require I unlock it, pull just a sliver out, and lock back in where the cart is practically touching the front of the loader area.

 

[tech3475]

Just reflowed the PRG, since that was the only thing left that wasn't replaced to no avail. As for the RAM chip it's a CX5864BSP-10L to replace the KM6264BL-10L, which as far as I can find from the datasheets should work. (8K CMOS high speed static ram with compatible pinout)

Could the ram chip be faulty?
https://wiki.neogeodev.org/index.php?title=RAM_chip

 

[nasune]

Could the ram chip be faulty?
https://wiki.neogeodev.org/index.php?title=RAM_chip

I'm not going to say it's impossible, but the board it came out of was working (main reason I scrapped that board was due to severe trace damage leading to the cartridge slots ). That and diode testing does suggest that it is working (all address/data lines test more or less the same etc.). Still I'll try to grab another one to see if that'll work.
One thing I do not understand though, is that the dump is 128kb (which is correct when checked against a known good dump), while these PRG chips (28 pin) are supposedly 64kb max. I guess it has something to do with the 161?

 

[tech3475]

I'm not going to say it's impossible, but the board it came out of was working (main reason I scrapped that board was due to severe trace damage leading to the cartridge slots ). That and diode testing does suggest that it is working (all address/data lines test more or less the same etc.). Still I'll try to grab another one to see if that'll work.
One thing I do not understand though, is that the dump is 128kb (which is correct when checked against a known good dump), while these PRG chips (28 pin) are supposedly 64kb max. I guess it has something to do with the 161?

It's late so I can't tell for sure, but it looks it:
https://www.nesdev.org/wiki/AxROM