Worklog cy's Unnamed N64 Portable (Worklog)

[cy]

It's finally time for me to build something other than a G-Wii, and no, I'm not talking another Wii portable. The scope of this project is fairly straight forward: Make an N64 portable with USB pass-through for an N64 controller HUB and Composite AV out. For those who don't know what this means, it essentially means creating a way to output audio and video on a CRT(or modern display with an adapter) while simultaneously having a controller solution allowing for 4 player multiplayer. This shouldn't be rocket science for me considering I was able to pull off something similar to this in my last project. The challenging aspect of this project comes in the form of it being an N64 which I'm yet to portablize.

This project has been in my cards for a little while now. I bought an N64 motherboard, PIF relocation board, and N64 Joystick converter board from @SparkleBear a year or so ago, so this was always something I had intended on doing. It wasn't until recently however, that I've actually gotten to work on this project. Progress has been real slow so far but that is in part due to my lack of components and funding. That's going to change soon though, and I plan to purchase a PMS1 from @CrazyGadget at MGC at the end of this month meaning I'll be able to successfully trim and test my board. I will still be waiting on other components such as a screen and other unaccounted for items that'll be needed, so I'm not expecting progress on this project to be fast.

With all of that said, I have removed and relocated the PIF, U8, and U3 off of the N64 motherboard. As of right now, the rest of my PIF breakout board is unpopulated, although I do have plans for how I intend to populate the rest of it soonish at least, so keep an eye out for that little update. Anyways, here's how my PIF relocation is looking:

I've tested all legs of PIF and U8 with a multimeter and everything checks out so far. I'm looking forward to populating the rest of this board soon and hopefully trimming and testing the N64 after I get back from MGC. As for the jumper pak, I plan on simply relocating an N64 expansion pak which I picked up at MGC in 2021 for better compatibility with games. I am aware that RAM swapping is a thing, but I'm afraid that is a little out of the budget and scope of this project - fitting an expansion pak in this thing shouldn't be too difficult anyways. I'd like to thank @SparkleBear for advice with this as well as for supplying me with the components I needed for cheap. I'd also like to thank him for supplying me with some of this knowledge in the form of his worklog which you can find here. Also thanks to @Gman for designing the PIF relocation board and everyone responsible for the Advanced N64 Trimming Guide.

 

[cy]

Update time: I've populated the PIF relocation board with resistors and caps, I'd like to thank @SparkleBear again for advice and help with this. He suggested I purchase a book like this one which has a lot of common resistor and cap values physically available within the pages of the book. This wasn't quite enough though, this book had almost all the values I needed, but it didn't have the 47k ohm resistors needed by this board. It did have values that were close, but to ensure the relocation was done correctly, I looked into alternative solutions. @CrashBash told me that resistor stacking is a thing, and after a bit of math(and totally not just pulling up a calculator for this on the web), I discovered that if I put 51k and 680k ohm resistors in parallel by stacking them, I'd get the 47k ohms I'd need. So resistor stacking and populating I went until finally:

I should've taken a side shot of the resistors so you could see they were stacked, but I suppose that is water under the bridge. Now my PIF relocation board was completely populated, although... It sure would've been nice to test and verify it worked... More on this later...

For now, I decided my best bet was to create a battery clip solution that I could easily implement into the portable as I'm tired of soldering directly to batteries. I shouldn't have to explain why this is a good idea and I actually already have some left over battery clips from my Ashida build. By "left over" I mean all of them because I wasn't able to get my hands on the right ones at the time and I was in a rush to finish it so I could bring it to MGC meaning I ultimately soldered to the batteries of that one. This left me with battery clips that I needed to design a solution for, so I did just that:

Here's how the final design turned out:

(let's ignore the fact I need to vacuum my floor)

This design was made for 18650s with specifically these battery clips(digikey part #36-209-ND). If anybody is interested in using this battery clip design for themselves, I'm including the model files in this post. Note that the scaling will need to be set to "2.54"% under scale factors in prusa slicer if you use the STL at it's current scale. It may also need to be rotated 90 degrees(note that the gcode of it is already scaled and rotated accordingly).

That's enough 3d design for now though, let's get to the more interesting part of this update post... The trim!

Originally I was planning on waiting to trim this puppy until I got the PMS1 I intended to power it with from @CrazyGadget , but I was really eager to continue my progress in this project and was dying to see if my PIF relocation would actually work. The problem is that even after trimming this thing, I still need a way to power it. A few weeks ago I ordered up two 18650s for this unit and I happened to have a singular PMS2 left. I didn't want to use it on this project or open it even really, so my original intention was to wait until after MGC... And then 4layer announced the return of PMS2's... With this, I was no longer worried about risking my precious last PMS2 and I decided to give the trim a go!

Here's what my outline looked like:

Notice how I removed many of the unnecessary components like the power switch, reset button and many of the caps with hot air. The caps could've easily been de-soldered, but things like the power switch were gonna take more than just a soldering iron to remove. I also wanted to preserve the controller ports since a controller hub with USB pass-through is in the works for this project. Really, if it was even close to being in the way, I either de-soldered it, or removed it with hot air.

With all of that, I decided to go forward with the trim and here's the result I got:

Yeah, I kinda made the cardinal sin of forgetting to take a picture of it immediately trimming and sanding it. This picture shows the trim after I wired up the PIF and necessary voltages. I put the OEM cooling solution on for the time being since I wanted to test it for a few minutes to ensure it'd continue running once I turned it on. With all of that, I very nervously wired up a composite out connector I had lying around, hooked it up to an HDMI adapter, brought in a monitor to test it with, and turned it on... The following was my result:


As you can see, it boots! This trim was a lot more challenging than any Wii trim I've done. Even after removing components that would be in the way there was still a lot of care that need to be taken to ensure this trim was a success: Carefully triple checking my outline, ensuring I had the right trim for my motherboard revision(this was a revision 2 trim), not cutting my fingers off by holding the board in a stupid way(that was a bit harder than you'd expect, the N64 doesn't have a lot to hold on to), and not butchering the traces that connect the CPU, RCP, and Cartridge slot together by not slipping with the dremel and correctly/carefully following the outline I drew. It's a lot harder than it sounds believe it or not, or maybe I'm just really bad at using a dremel. Either way though, the trim is complete and it was successful as was my PIF relocation! Next update will likely be a little ways out, but I do plan on doing some case design in the meantime so who knows?

Thank you to @CrazyGadget @CrashBash @Gman @SparkleBear @That_Random_Guy (you know everything you did to help with this project ) And last but not least, @Y2K . You're all awesome!

 

[cy]

I am aware that RAM swapping is a thing, but I'm afraid that is a little out of the budget and scope of this project

SIKE!

Not only did I lie to all of you about not doing a RAM swap, but I lied to myself as well. Turns out I had a spare expansion pak lying around that I wasn't aware of... I still wasn't planning on doing this until I realized I'd have a much better time designing the unit around a jumper pak relocation than I would an expansion pak, so... I now proudly present my trimmed 8MB N64 with a jumper pak used to close the circuit instead of an expansion pak.

Here it is booting into Majora's Mask:

If you watch the full video, you'll find that Majora's Mask states that the expansion pak is undetected in the unmodified N64 and obviously is detected in the trimmed one. The point of this is to showcase what happens when you boot into MM without an expansion pak. Here's some better shots of the RAM swap:

(Getting one side angle with both sets of pins in focus proved impossible, so I ended up taking several pictures of it. These three pics do the best job showing off my work)

This ought to make the internals cleaner and the case smaller.