Repair/Restore my Nintendo M82

I think I finally figured it out. In my frustration, I completely removed the motherboard from the case. It's completely out.

It appears as though one of the pins where the Texas Instruments PIC plugs into on the motherboard is completely broken. I checked with a multimeter, and it is NOT making contact with the other side of the motherboard!

I am taking out my soldering iron now to try and repair.

And...while I am in there with my soldering iron, is there any way to wire this thing up so Super Mario Bros 3 works in it? I could have sworn someone once said the IRQ line just needs to be wired up to the CPU, or something like that. Figured I would ask while I am in here.

 

Thats good news

My SMB3 sort of works, its got slightly garbled display (Thought it might need a clean - Gremlins 2 displays the same way?

 

Really? I heard no games using MMC3 work properly due to the IRQ line not being hooked up?

 

Mine plays but with graphic corruption but not thought it was the cartridge not a known issue... Weird... What supposed to happen with Mario 3 running on the system?

 

I believe entire graphics do not show up. BunnyBoy wrote a huge article on the M82, and said Super Mario 3 was one of the few games that do not work. He had said the M82 does not have the IRQ wired up. I was wondering if there was a way to do it

I am putting my system back together and I forgot to take "before" pics. I am looking at your Photobucket and unfortunately this section was not photographed by you. Any idea which way this cable is supposed to be plugged in?



You can't see it but the left peg has an arrow pointing to it. Not sure what the arrow means. Is the brown or the blue wire supposed to be on the left?

 

Thats odd, I can play my SMB3 ok but with corrupt graphics :S

I don't have a picture of where its supposed to go and it's a bitch to get my M82 out from under the telly (Got to move a tonne of shit).

Plug it in the way it feels natural and should be ok... I connected mine incorrectly before and nothing bad happened... Just power on before putting the top back on to confirm all ok.

 

IRQ is used by MMC3 based cartridges to tell the CPU that a certain line was achieved by the raster. On SMB3 it tells the CPU it has to start drawing the scoreboard panel.

Since the game doesn't draw it properly without the IRQ you probably see graphic trash where the scoreboard panel would be normally...

 

That would explain it... Is Gremlins 2 the same deal?

 

Normally if a multi wire connector has been in place for a while, it will hang in its correct orientation when unplugged, based on that I'd connect with the brown wire to the left (I'm always surprised by tales of people cooking 360 drive PCBs by connecting backwards, the wires are pretty stiff and hold their position when disconnected.

That thing is SUPER CLEAN inside, how did you get it like that?

 

I was just lucky with it being really clean. Thanks man, I have plugged it in so brown is to the left. It's just as easy to plug it in backwards.

Here's what ended up happening. I noticed this:



The 2nd to last hole had a cracked peg! I checked with a multimeter, and it wasn't making a connection to the other side of the motherboard! So I assumed for sure I had fixed it. I replaced the entire piece by desoldering it and I had another one of them lying around that I just bought: http://www.ebay.com/itm/180953229154

Here's the weird thing. Now that I repaired it, I plugged in the programmed chip you guys were nice enough to return to me. No more grey screen! It boots to a game every time! However, still no controllers will work??

I can't imagine what could be going on? I luckily found my old chip and though it's corroded, I soldered it to another DIP20 IC socket and plugged it in and I get the same result. Game boots always now, but controllers will not work!

Here is the way I have the controller ribbon cable plugged in:



I believe that's correct? Regardless, I tried it in the other direction and swapped sides. No dice.

Here is the way other plugs look, no idea if anything is out of wack, but again I've tried every variation I could think of:



Could anything be wrong with this thing?



The 3rd port from the left says "CN1" on it so I assume that's the first player port. Not that it matters, I've tried every damn port with 9 different controllers.



What could be wrong?

 

Try checking each chip with an multimeter, and make sure the controller chip-set and ports are correctly fine. Gamester81's M82 controllers are plugged in the first and second ports (video about it or this image).

 

Awesome news ! Now to trace the controller inputs and see how they work.

 

Is there a component missing from location C9 in this photo?

 

Good eye. But looking at K1ngArth3r's PhotoBucket it appears that it not being there is intentional?

http://s376.photobucket.com/user/K1...do M82/PSU_1_zpsa5d3e2b4.jpg.html?sort=4&o=27

I know it's weird that it's marked "C" for capacitor and there's nothing there, but looking at K1ngArth3r's motherboard photo it appears to be intentional?

Thanks for this. Maybe for some weird reason both controllers need to be plugged in. I will give that a shot (though I doubt it could be it; I am willing to try anything!)

Dumb question but were you recommending I do something here? I am confused.

 

Yah I was recommending that you try tracing the controller inputs from the controller to the CPU chip, you might find a broken trace or corroded socket (hint hint)...

 

Ah okay. I have no clue where to trace from/to though! I didn't even know the controller goes to the CPU chip!

 

Not directly, it pass through a buffer chip, so you have the buffer chip in need of checking along with the traces. Also because the system is a specialty with a timer, it might have some sort of mechanism that stops the kids from playing on it for too long.

 

Okay so I am at a standstill here. What else should I try? What could be wrong with this thing?

 

Did you do what was suggested above? Without tracing everything put, you probably aren't going to fix it

 

I am just really confused as to trace from where to where?