Sifuf's expansion pak relocation guide

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SifuF
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Sifuf's expansion pak relocation guide

Post by SifuF » Wed Aug 06, 2008 1:48 pm

EXPANSION PAK RELOCATION


Relocating the RAM is probably the ultimate dream for an N64 portabliser. It is the only real way a comfortably thin machine can be built. But it seems many of us have struggled with this task.

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First of all, I do not claim to be a soldering God and I am NOT responsible for any damages you may cause to your self/equipment while following this guide.

Now that’s out of the way, onto the guide!

It's actually not that difficult, providing you follow a few simple rules

You must:

1. Keep the wires a short as possible:
This is essential. The speed at which the CPU communicates with the RAM is critical. Attempts with wires more than about 20mm in length will fail.

2. Keep the wires equal in length

3. Wire ALL of the pins (Even the multiple GND's):
This is probably not essential, but not doing so is bad practise, and could increase your chances of it not working.


EQUIPMENT LIST

Soldering Iron (I use a 15W antex iron with a point tip)
60/40 Solder
Flux (paste flux is better but a flux pen will do)
Loupe/Eyeglass (at least 8x magnification)
Wire wrapping/Kynar wire
Ohm/multi meter.
Wire strippers/cutters
Pliers, mini screwdrivers.


REMOVING THE PORT

First, open up the N64, remove the metal shield and place the mainboard in a well lit and static free environment.

Remove the heatsink for the RAM to allow better access to the expansion port.

De-soldering the port can be messy and very easy to pull traces right off the board. So I propose a different method.
There is very little solder on the pins and the whole port can be snapped off without too much difficulty.

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First, use a small flat head screwdriver to pry up the metal shield from within the slot and then use pliers to break it off, taking EXTREME care not to slip with the pliers and scrape them across the PCB.

You are then left with just the plastic part of the connector which houses the pins. This can be snapped off by GENTLY bending it towards the RAM and back again until u can pull it right off. Most of the pins will lift off with the connector, but few will snap and stay on the board. Remove these remaining pins by heating the pads with your iron and pushing them off with a dragging motion. Finally run the iron over each pad so it looks nice and shiny. I have used this method 4 times on different N64's and not once have I lifted any pads or damaged the board in anyway.



HARDWIRING THE EXPANSION PAK

Remove the power indicator LED from the N64.
Open the expansion pak, discard the heat plate and position it flat up against the pads on the N64.

(The N64 PCB in the following pics is dead and has damaged traces. I am using it here for demonstrative purposes. The expansion pak is a third party one, but I would recommend using the smaller official Nintendo pak as they contain just one 4meg RAM chip as opposed to 2x 2meg shown here).

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Fix it in position using some double sided tape. WARNING.... Make sure the pak will not short out against the N64 mainboard.

Now you can begin the soldering.

Tin each pad on the expansion pak by heating it with the iron and at the same time adding a SMALL amount of solder. If you use too much, bridging will occur.
Cut a small piece of wire to the exact length needed to contact the pins and strip it at both ends.

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Hold some solder with the iron tip and use it to tin the wire. Again, only put a VERY small amount of solder on the wire otherwise you will bridge the pins when you come to solder it to the board. Take a cotton bud and apply some paste flux (or use the pen) to the pads on the N64 and the expansion pak.

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Now hold one end of the tinned wire in place against the first pad and solder it down, by touching the iron to the wire and slowly dragging it along the pad to sufficiently heat it.

Remember, you are not applying any solder directly to the N64. You are tinning the wires and then using just the iron to bond them to the fluxed motherboard. Then solder the other end to it's corresponding pin on the expansion pak using the same technique.
Don’t get confused by the pinout. Top pins are odd, bottom are even. The large pin on the left is both pin 1 and 2. The large pin on the right is just pin 36.

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I prefer to start at pin 36 and work my way down.

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Now take the loupe and thoroughly examine your work to make sure you haven't bridged anything. If you do not have a PERFECT joint, de-solder and redo it because faults left until the end are much harder to rectify. All is left is to work your way along all the pins, using this same technique.

As you can see from the following pics, every other wire has been completely stripped of its insulation. This was my preference, and up to you if you want to do it this way or not.

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BEFORE INITIAL POWER ON

Upon completion and before you plug it in and risk frying the machine, spend about 30 mins inspecting your work.
Take the loupe and examine each connection. If you aren't 100% sure there is no bridge in some areas, then redo that pin until you are.

Then take the multimeter and set it to its ohmeter function. Test between each pin and compare your results to those in the following diagram. The pins should have no continuity (or a high resistance) between them unless they are of the same colour. You will then be able to tell if your reading between pins of 0 ohms is due to them both being grounds, or because you've made a short.

This pic will also aid in your repair if you damaged any of the traces during the removal procedure.

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Make sure you've got all the heasinks back on (including a suitable one for the extra RAM) and that there is nothing conductive on the board. Check for tiny bits of wire that have lodged themselves tightly between 2 pins on the CPU (That’s how I lost the board in this very tutorial!) take a deep breath and power it on. If it works, then well done, you are a soldering hero!

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IF IT DOSEN'T BOOT

Try re-seating the cartridge a few times, but if it still fails to show video, turn it straight off and find that short!!! (there's always one...... believe me!) Redo every connection that isn't perfect and compare the pin readings to the diagram over and over again. Don't give up. You WILL eventually find it. Also..... don't think that if you've rectified a fault and it still doesn’t work, that the board is fried because it most likely is not. My first attempt had several shorts and only after I found them all did the board finally boot up. I thought for certain it had fried.

I hope you enjoy this guide,

Sifuf

EDIT by Skyone: imageshack has thumbnails for a reason. :P
Last edited by SifuF on Wed Aug 06, 2008 4:29 pm, edited 1 time in total.

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HazmatB
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Post by HazmatB » Wed Aug 06, 2008 3:02 pm

Great guide! This is exactly what I was looking for. Thanks a lot!

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Post by Skyone » Wed Aug 06, 2008 3:34 pm

Amazing guide with some amazing pictures and a solid way for checking your work.

However, when I did my relocation, I think I got about 1.5 inches (just of 30mm) of wire with it still working, but I suppose that was pushing it. I did this to wrap the expansion pack over to the other side of the board.

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SifuF
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Post by SifuF » Wed Aug 06, 2008 4:22 pm

Skyone wrote:when I did my relocation, I think I got about 1.5 inches (just of 30mm) of wire with it still working, but I suppose that was pushing it. I did this to wrap the expansion pack over to the other side of the board.
Interesting. I also thought about wrapping it around the back of the board. Great to know it works.
I was originally succesful with short wires, so I lengthened them to 100mm, then reduced to 80mm and then further still to 40mm. All of these lengths were unsuccessful.
I guess we can say 30mm is an absolute max then?

And obviously there are other factors involved in addition to length of the wire (CSA and Resistivity of wire, type of solder, etc...)

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Skyone
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Post by Skyone » Wed Aug 06, 2008 4:57 pm

This is just going off memory really, the portable which held the relocation has been long sold. However, I'm going to be doing another relocation soon which I'll be wrapping wires around to the underside of the board; so I'll reconfirm it soon hopefully!

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Valium
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Post by Valium » Wed Aug 06, 2008 5:07 pm

Great information, if I ever make a N64p I'll try this.


Question though, I know the jumper pack doesn't actually have anything in it, so how come the system won't turn on without it? Are there some pins on the N64 board that need to be bridged in order for it to work?
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Post by grossaffe » Wed Aug 06, 2008 5:13 pm

Valium wrote:Great information, if I ever make a N64p I'll try this.


Question though, I know the jumper pack doesn't actually have anything in it, so how come the system won't turn on without it? Are there some pins on the N64 board that need to be bridged in order for it to work?
probably. Kinda like how Rambus ram has to be done in pairs. if you don't have the second stick to go with it, it doesn't work unless you get a terminator (I think that's what it was called) stick.

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HazmatB
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Post by HazmatB » Wed Aug 06, 2008 5:20 pm

Valium wrote:Are there some pins on the N64 board that need to be bridged in order for it to work?
Short answer is yes.

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Post by Skyone » Wed Aug 06, 2008 5:22 pm

Well that's what a jumper is used for, to jump pins. :P The two on-board RDRAM chips are linked together to form 4MB of RAM, and they are also set up to be linked to whatever is plugged into the RAM expansion port. The jumper pack simply has no RAM, and in short; loops back to the original RAM signifying that there was indeed no memory appended.

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Post by Valium » Wed Aug 06, 2008 5:22 pm

So which pins need to be jumped?
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Post by Life of Brian » Wed Aug 06, 2008 5:26 pm

Excellent tutorial! Now we can all have our expansion packs and keep things slim. Thank you for providing the instructions!
dragonhead wrote:sweet. ive spent a third of my life on benheck!
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HazmatB
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Re: Sifuf's expansion pak relocation guide

Post by HazmatB » Wed Aug 06, 2008 5:28 pm

@Valium:
SifuF wrote: This pic will also aid in your repair if you damaged any of the traces during the removal procedure.

Image
I believe just the ones with matching colours here.

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Skyone
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Post by Skyone » Wed Aug 06, 2008 5:31 pm

Incorrect, Hazmat. Between some of the lines, there are resistors and capacitors. Would you like me to draw a diagram of the jumper pak? I suppose it could come in great handy in slimming things down to the max. :P

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Post by HazmatB » Wed Aug 06, 2008 5:33 pm

Oh, thanks for the correction Skyone. I know I would appreciate the diagram of the jumper pak. I could just follow the traces myself though.

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Post by Skyone » Wed Aug 06, 2008 5:45 pm

The diagram pictured actually shows the majority of the connections, just not any of the components. So you can go off of that if you'd like, too.

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