Board bending - N64 expansion pack / jumper pack

Why bother you ask? Well, when making an N64 portable, the expansion pack sticks out a bit and short of soldering skills to RAM swap the chips and remove the caps from the jumper pack to the N64 motherboard directly, which is risky, I came up with a simple method of getting the jumper pack or expansion pack flatter - board folding.

Expansion pack

This is actually REALLY simple!

Only took 2 wires to do it!

Here's the back of the expansion pack (removed the bit of grounding off the edges of the board BTW).



Surveyed what's what and found that the line under the "C6", "C7" and "C8" is in just the right place, and the only points the two contacts under "C7" and "C8" only connect to each other. Below is the line we need to cut. Clearly, the only contact then that needs rewiring apart from the above, is ground.



So, easy to turn the board around and add a dot of flux to the two points as indicated and attach a wire between them - that connects the two pins under the "C7" and "C8" as mentioned.



ie



So, cut through the board with a Dremel to about 80% or so all the way through, not cutting through of course or the traces will get cut.



Folded the board and reconnected the severed ground with a small piece of fairly thick (3 amp) wire.



I know the chip needs a slim heatsink, but this is to show the board done



Proof it works fine:



As you can see, the expansion pack is only around 3mm higher than the height of the expansion pack port itself. This is a safe mod to do as it doesn't need any modification to the N64 motherboard.

Jumper pack

wire three wires (using standard 1 amp wires) as per the pic. No work needed to do to the original port BTW, pop the jumper pack in as normal.

Tested on a few games, works great.

Point is of course that you can have the jumper pack laying lower in your case with this method, without having to remove the port and wire thin wires to the contacts, which can be a good way to kill a board often; this method is safe and easy to do, in comparison.

These pics should show what was done and what the three wires connect to.

This is a simple mod, on reflection, would have been easier if i'd cut more like 90% of the board through, ie until you can see the light through the board cut but obviously not enough to cut through to the other side.

 

Soldering directly to the board is an INFINITELY better idea. This is just asking to get broken by looking at it funny. Nice that it works but that doesn't begin to remotely qualify it under the "good idea" category.

 

If you mean the wire under the chip, it's soldered properly in place; a bit of superglue would keep it there permanently, or as you say, solder to the pins on the motherboard to do the same job.

Normally, you'd put in your heatsinks on the memory chips on the motherboard, and on the expansion pack, and have it so you'd then be able to superglue (using tiny dots of glue) the heatsinks together, meaning the expansion pack isn't going anywhere.

The point of the mod is to have the expansion pack or jumper pack as low onto the motherboard as you can, easily, without damage to the motherboard itself, and needing a low-level of modding skill to do it. Other methods need fine soldering and even then, there is a good chance of ruining the motherboard in the process; which this method doesn't suffer from.

 

Nice trick, but poor pcb. Dunno if I think its a good idea for beginners. So all modders aware, this method can break your pcb if bend to far or pcb is not as strong as example here. You dint wanted to relocated the connector, or change the mobo ?

Pcb is Printed Circuit board, the green thing with the black IC on it.

 

If anyone reading this doesn't know what a PCB is they shouldn't be modding, haha.

The process is easy to perform but of course the board is considerably weakened as a result, which doesn't matter if it's secured in place and not going to be removed again (hence middle paragraph in my last post). You can bend a board back onto itself fine, once; or as this case, at right angle; if you try and do it more than once then of course the board will weaken and snap - once is all you need though.

The board itself is the usual material they use for motherboards.

Relocating the port needs fine soldering skills too as the contact pins are very close together; which is an issue for people less experienced with soldering for sure.

 

Your idea and tweak is Awesome, I personally feel more comfort by modifying the Port. but sometimes I hear ppl trying the Difficult stuff without thinking
get me thinking of doing a portable myself.. left overs ps1's.

 

This won't modify the width of the vias on the board? Causing the signal to lose it's integrity... :S

 

The traces are all intact, only ground is rewired and one trace reconnected, no issues.

 

With all the complexity to do this to a N64 expansion pack, I might rather get 2 of the single chip packs that had the 4mb chip and replace the 2mb ones on the main board. Expansion pack built in. Ditch the slot and hardwire the circuit from jumper pack in place. Done.

Photo:


This board has 2 of the 4mb chips on it. I think this method of wiring the jumper pack is overkill and less wires are needed IIRC. I'll have to see if I can find the discussion on it again...

 

That is the neat way of doing it, yes, however isn't for the faint hearted to attempt.

 

Not good for beginners since you have to cut the board. Although it's an awesome mod don't get me wrong.

 

For absolute beginners I never suggest doing any board trimming or reduction at all; however as people get more experienced then when they are at the stage of basic board trimming, then a simple score in a board to fold it back and a couple of wires to re-join is very easy. It is a "low risk" method.

What is hard is the likes of:



The chance of frying your board doing that is quite high and should only be attempted by experienced modders with a steady hand for soldering; this is a "high risk" mod, although if you can do it, great!

 

Nice mods! I did the 2 x 4MB mod a while back, but I gave up trying to solder the resistor arrays to the mainboard.
(I used to think my soldering was pretty good, but that above pic was very nicely done I must say).

Just to clarify something interesting - if you look at the pads on the expansion pak which connect to the N64 itself, all the pads with a via (dot) connect through to the ground plane on the underside of the pak...
The wire which @bacteria added connects the "SIN" signal on the Rambus chip to the N64, but the trace directly below the left-hand end of the wire / via isn't actually connected at all (there's a tiny gap).

(They probably left the ground trace there to help reduce noise on the signal.)

The "SIN" / "SOUT" signals form a chain like this ("+" signs denote a wire / connection)...

1st chip (U14)..........2nd chip (U11)........Exp port
SIN+++3V3
SOUT++++++++++++SIN
.............................SOUT+++++++++++SIN
........................................................SOUT+++GND


The SIN / SOUT chain is used to initialize each chip...
The SIN pin of the first chip is tied to 3V3, so at power-up, this tells the RCP that this is chip 1.
The first chip then outputs a "1" on it's SOUT pin (which goes to SIN on the next chip), the RCP then knows which is chip 2, and so on.

Hmmm, I wonder if anyone's tried adding more than 8MB RAM to an N64 and if the RCP will actually map it?

btw, does anyone here have any PCB layout experience?
We could still make a complete replacement PCB for the N64 with everything on it you can imagine (FPGA / SD slot / RGB / VGA / HDMI / Universal PIF etc.)

The PCB could be made a fair bit smaller but still include the best of each feature.

Just a thought. :smile-new: I've been sitting on this project for many years now, but can't find the motivation to get back into it.

OzOnE.

 

Stupid question, but does shoving an expansion pack in a 2x4MB board detect 12MB or not?

Just curious, since some titles scale memory allocations based on detected memory, and it would be interesting to see the result of that.

 

I was wondering along the same lines a while back. But I was thinking of the expansion packs that have 2x 2mb chips in them. Replace all the chips with 4mb models to end up with 16mb RAM. I always wondered if any games would scale up to this and increase performance at all. That and the infamous 200 mhz overclock to get Golden Eye to play smoothly.

These mods= super-turbo-charged N64.

Add RGB mod to the early models and we have NOS thrown into the mix as well.

ED64 or 64Drive and we have sticky drag slicks and a suspension to hook them with.

All that's missing is a cool shell to house it all in like say a Fox Mustang. Portable 64 anyone?

LOL! Listen to me compare N64 modding to USA drag racing...

N64, a powerhouse that never quite saw its full potential...

 

This helped a lot.