Reverse engineering the jumper pak.

[bentomo]

Now that it's easy to put in an expansion pak if you have the right tools by replacing the ram chips. All we have left to do is make our own jumper pak. Now lets get started.

Here is an official nintendo jumper pak, revision 3.

Here's it disassembled.

Here's the front.

Here's a closeup of the traces. Black lines are ground.

Here's the back.

Here are the back components.

Here is a N64 without the jumper pak slot.

Here are the two kinds of components. Red circle is the resistor pack, each one measuring 51 ohms. Blue circle is a surface mount capacitor, 3.3 microfarads.

Here's the wiring diagram I made.
RED: Pins are not connected to anything
Black: pins are ground, remember to tie the ground to all the correct ends of the components
gold: common component connection between all components (except capacitor 5) and two pins
BLUE: pins connected to components
pink. two pins need to be bridged.

LATER REVISIONS OF THE JUMPER PAK DON'T HAVE THE 5TH CAPACITOR, SO PIN 23 CAN BE LEFT UNCONNECTED TO ANYTHING

Here are some notes I took while doing this.

1. Copper pins pattern starts high on the left and ends low on the right.

2. 9 pins are not connected: 1, 4, 10, 14, 18, 23, 33, 34, 35

3. 11 pins are ground: 2, 6, 12, 16, 20, 22, 24, 26, 30, 32, 36

4. 2 pins are connected to eachother: 3, 17

5. 2 pins are connected to common component connection: 8, 28


What are the benefits of this?
Even if you relocate the jumper pak, a little bit still sticks out of the front of the n64. Also if the values are figured out then you can make your own jumper pak. And knowing what pins you can bridge like ground and what aren't connected are nice too.

Please point out any mistakes.

This has been confirmed working by several members of the forum.

 

[daftmike]

I did this quite a while ago using the components from a jumper pak and carving room for them on the n64 board. It's quite messy but works well and saves a fair bit of space. I can't say how accurate your tracing is but it's certainly possible.

 

[bentomo]

There I go again doing something that totally wasn't necessary.

 

[daftmike]

Of course it's always better to document the process for others to use, I just didn't think people would find it useful at the time.

 

[bentomo]

But there are different revisions of the jumper pak without the 5th capacitor so I need to figure that out.

 

[ShockSlayer]

I did this quite a while ago using the components from a jumper pak and carving room for them on the n64 board.

I did that the exact same way a while ago, cutting down the board, dremeling some space and everything!

SS

 

[Mario]

Skyone already posted this, too.

That looks slick, daftmike.

Also, I found the 5th cap isn't needed in the jumper pack. I cut the trace, made sure there was no connection, and tried it. Worked fine.

 

[Basement_Modder]

I did this quite a while ago using the components from a jumper pak and carving room for them on the n64 board. It's quite messy but works well and saves a fair bit of space. I can't say how accurate your tracing is but it's certainly possible.

I was in the process of doing this exact thing. Now with this picture and thewise1's pinout, I have to do virtually no work!

 

[Basement_Modder]

Did it last night. It works. HORAY!!!

My camera is only a 3mp, so I will try to use my friend's dad's 15mp one to take a pic.

 

[bentomo]

You did it without the 5th cap right? It's not that I don't trust mario but I like when it's confirmed.

 

[Basement_Modder]

You did it without the 5th cap right? It's not that I don't trust mario but I like when it's confirmed.

My pak didn't have the 5th cap at all, so yes.

 

[ShockSlayer]

You did it without the 5th cap right? It's not that I don't trust mario but I like when it's confirmed.

My pak didn't have the 5th cap at all, so yes.

I had one that had 6 caps...the expansion pack has, like 8.

SS

 

[bentomo]

Well I tried it, no luck, I tried it without the 5th cap, which should have been fine. Although the led still lights up So I'm pretty sure it's not fried, my multimeter shows no shorts anywhere. I think my wires for the common connection are too long, I think they're over two CM. I'm probably going to try again tomorrow.

 

[Basement_Modder]

I kept the wires at about 5mm. No need to make it far away.

 

[bentomo]

It's not far away it's just that it wraps around it. I'll try to figure another way around it. (get it? )

 

[Hifeno]

I have a question. If I replace the ram to make a built in expansion pack do I still need the jumper pack or something else.

 

[Mako321]

I have a question. If I replace the ram to make a built in expansion pack do I still need the jumper pack or something else.

You still need a jumper pak, but that's it.

 

[kos]

I did this quite a while ago using the components from a jumper pak and carving room for them on the n64 board. It's quite messy but works well and saves a fair bit of space. I can't say how accurate your tracing is but it's certainly possible.

what did you do in this pic? did you cut the jumper pak? if so where did you cut it

 

[Basement_Modder]

 

[bentomo]

You can already see the copper traces, it's the lighter green silicon. It's a very simple circuit.