zzattack

Another clone. Credit to original sickmods design, this is electrically 1:1 with the addition of pins for the programming header on the right side. Contrary to all the other clones this one actually publishes kicad schematic + board layout, instead of a PNG of the .sch and gerber output, since I really do not care if someone wants to modify this or put their name on it. https://github.com/zzattack/xerc2/releases/tag/v1.0

Yes, on the xbox motherboard. lOgIcAl was asking about the interposer pcb.

Normally yes. This is why in the rev2 design no via in pad is used and I've made a considerate effort to keep vias away from silk screen. However, I then found out that jlcpcb charges no extra for POFV: : https://jlcpcb.com/blog/32-Free-Via-in-Pad-on-6-20-Layer-PCBs-with-POFV In this case, this is very attractive so I made rev3 specifically to take advantage of this.

Small necro-bump on this project. About a year ago I had started to 'delayer' a n64freak interposer for the purpose of revealing its inner layers, allowing me to scan them for reference and potential recreation. Being unfamiliar with KiCAD there was some interest in learning about it, so as a way to build up experience I began to redraw the schematics from the original FriendTECH. This did not take excruciatingly long since it is mostly a point-to-point hookup between the two CPU footprints, with only very minor circuitry added. I completed the schematic, but after speaking with Kekule who had done a similar exercise I did not persue this effort further, since his files would eventually be released. Then, when the Kekule interposer gerber release was announced 2 weeks ago, I felt somewhat disappointed that 1) I never completed what I started and still hadn't used KiCAD for layout, and 2) neither schematic nor pcb layout files were released along with the manufacturing files. Therefore I set out to take a stab at resuming where I left off. Initially I overlayed the delayered scans with the positioned footprints and began to trace them into the copper layers. This went well for the 45° angled signals but eventually grew old quick. Later I found a way to convert the Kekule gerber files into editable paths which I could place into the layout, and after annotating them with the correct schematic nets I ended up with a completed board reasonably quickly. This was to be revision 1, yet another clone of the 20 year old design, now with the benefit of having the actual editable design files along with them. Oh, and the useless clock reduction circuit is chopped off. Now the original design has the major drawback that the BGA footprint is in the corner of the board, which causes one of the original heatsink bracket mounting holes to be covered, and during reflow the uneven distribution of the weight can cause the interposer to tilt/slant during reflow. In the MakeMHZ discord, user 'doom' had flaunted some pictures of his interposer which was not a clone but a full remake. It looked very very clean, did not have the BGA footprint in the corner, and seemed like an overall massive improvement over the original. My next challenge would be to offset the BGA pads in a similar way. This would of course require that I re-route the entire board. I was told by Kekule that the FriendTECH routing was absolutely next level and despite him having a lot of PCB engineering experience, he could not get the trace lengths to match up within the requirement of 1/10th inch for all of the data lines. This withheld me from taking a stab at it myself. I've done some PCB design up to 4 layers, but never considered myself expert-level, so I expected this to fail quite miserably. After putting my kids to bed at 9pm I sat down and didn't get up until it was fully routed at 3am. In about 6 hours I drew up what I thought would take me weeks, if I could even do it at all in the first place. The result of that was uploaded as 'revision 2'. I later cleaned up some of the silk screen, ensured no silk screen is printed over the vias, optimized the power planes a little bit and placed an order at JLCPCB for revision 2.1. The layout I drew up conforms to quite liberal design specs with 5 mil traces and 0.3mm drills and does not make use of via-in-pad technology meaning that to breakout the BGA signals, a small bit of trace is required and via's are placed in the center of 4 surrounding pads. This complicates routing of course since more real-estate is required for every pad. The advantage of using such design specs is that board houses typically start charging extra for smaller drills, so it can be produced very cheaply: there's a $2 for 5 offer on JLCPCB. The revision 2.1 board looks very messy compared to the aforementioned clean board made by doom. Looking at it closely, he seems to have made use of via-in-pad technology, allowing to directly break out from the SMD/BGA pads into the desired signal layer. Figuring this would take a ton of money to have produced I looked up a quote at JLCPCB and found that the additional premium is very reasonable actually. I'm considering doing another re-route where I'll aim for a really clean layout while making use of this additional capability. For now, here's the true open source designs: https://github.com/zzattack/xbox-cpu-interposer Thanks for reading

So cerbios formatted scheme remains unsupported?

I recently got asked for some tips on this upgrade and figured others could benefit from the info as well. So for posterity, here's what I recall as being the most relevant info, condensed. There's 2 important topics to get right which require some strategy: alignment needs to be dead-on, and the interposer needs some help to be mounted flat. I'll explain why. For alignment, generally you can be just under half a pitch off with your BGA alignment and it'll work out fine when the chip settles. So, the BGA pitch on this motherboard of 1.25mm suggests alignment is very forgiving. However, vias centered within groups of pads are not nicely tented, and instead take up most of the leeway you'd normally have with alignment. I'd say you don't have ~0.6mm of tolerance, but rather about 0.15mm. To assure I get good alignment, the first thing I do is eliminate the possibility of bridges forming between the BGA pads and nearby vias. You can simply tent these vias manually using UV curable solder mask. Takes about 10-15 minutes, and with this, a lot of alignment margin is recovered. At the same time, I place some 0603 resistors near corners of the BGA array and interposer outline. See the red marked circles below. The BGA pads on the underside of the interposer do not cover the entire interposer area, so the interposer tends to tilt/slant during reflow because it's gravity center is off. When the interposer is tilted, BGA balls can get too compressed and are unnecessarily stressed. Now the 0603 resistors just happen to have a height very similar to properly compressed 0.76mm solder balls, so this very simple approach ensures the interposer will get mounted flat. Next, my definitive way to get perfect alignments, after a number of less precise prior attempts: I drilled through the corner BGA pads on the underside of a sacrificial interposer. See circles in picture below. The resulting holes allows to see the xbox BGA pads underneath, and thereby align the sacrificial interposer perfectly. Then, I tape it down temporarily. The next step is to fix this interposer in place. The idea is that by placing e.g. 0805 capacitors along the edges of this interposer, we can lift it up and replace it with a fresh interposer in exactly the same position. Furthermore, because the interposer cannot move laterally, the interposer won't "dance", and therefore balls cannot join with the vias centered within groups of pads either. With the alignment also being spot on, there shouldn't be a "snap" when the BGA aligns itself due to surface tension either. I believe this thoroughly eliminates everything that could potentially yield faulty mounts. The very last optimization I added was to place a single case screw diagonally over the interposer as depicted above. This counteracts the weight imbalance due to the BGA pads being off-center underneath the interposer. The positioning I found is determined experimentally and results in the interposer settling down perfectly straight, i.e. all 4 corners go simultaneously. This isn't super important since we already guarantee flat mounts due to the 0603 resistors acting as standoffs from a prior step. Running short on time for this writeup so I'll conclude with the only other vital step: use a bismuth compound solder paste for the CPU itself. Bismuth solder has much lower melting point than normal leaded, so this allows soldering of the CPU without inadvertently reflowing the interposer (but with a lot of added weight on top, potentially squashing the balls!).

Well, I finished my batch and moved on. Maybe stellar will revigorate some interest. The only one I've got left is spoken for but I might do another few when I can get my hands on some stellars.

I've found my interests gradually shifting away from the xbox cpu convresion. That's not necessarily all bad, it mostly means I've achieved what I wanted. Both cooling solutions (glued/screwed) perform fine and I believe all of the kinks in my process have been ironed out. I did build up a nice stack of consoles to convert, and have indeed converted a fair bunch of them. A few sold through ebay quite easily, and a few through discord/twitter. I still have a few more available, maybe there's some interest here, so I'm putting two up for offer here. I'd like €250 + shipping for the one on the left, 1.4 revision with glued heatsinks. The one on the right is a 1.0 with screw mount heatsinks and open xenium priced at €300. Price excludes shipping. Both are complete systems with dvd player, hdd and shell. The 1.4 is 230V and the 1.0 can be sold as either 110V or 230V on request. Aside from the CPU upgrade they have 128MB of RAM, are recapped and the board is ultrasonically cleaned.

Haven't got around to setting that up, but the first few have sold. They run off 230V but swapping the PSU is al that's needed for making them work on 110V. I'm still actively looking for ways to improve the heatsink mount. They are fairly difficult to position entitrely flat on the cpu heatspreader.

Not exact numbers, but close. Didn't keep a record since in the end, they are all fixable. Unopened, working OOB: about 10 Opened before, but still working: about 7 Unopened, slight defects (front panel buttons/clock cap damage/poor DVD): 3 Opened, slight defects: 4 Unopened, not working at all: just 1 Opened, not working at all: just 2 The 'not working at all' were actually easily fixed by capacitor replacements. In fact, the "slight defects" are more work to fix because it usually involves trace repair due to supercap leakage. Two DVD drives ended up having no laser light at all. Some others required slight pot meter tuning.

They're traded at very low volume so estimating their value is hard. But the point about rarity has some merit. When I'm dumping 20 at a time, it's clear I'm not expecting all, or even any of them to fetch top dollar. That said, I've carefully deliberated the price point at which I want to offer them fully kitted with recap + clock reduction circuitry + 128MB upgrade and cleaned shell + dvd drive + hdd. I'm not exactly sure how much deduction is feasible when it's just the bare "motherboard with upgraded CPU" and none of the rest. But it does save a lot of time. And it allows me to discard non-working parts instead of fixing them. On the other hand, if everyone ends up buying just the board because it's cheapest and they'll either not care for or do the other upgrades themselves, then I'll have a ton of cases to discard of, which is also not ideal. I'll decide on that soon, once I get some e-commerce thingie going on a website. I think it'll be around €275 for the bare upgraded board, and it'll save a fair bit on shipping too probably.

Just dumping a progress picture, will get through it all, eventually.. On the acquisition front, the last batch of 4 xboxes purchased were advertised as good working condition, but in reality came with a bunch of non-disclosed issues: 3x non-functioning dvd drives (1x tray doesn't open, 2x won't read discs), 2x clock cap damage, 1x missing HDD (seriously!?). I'm not even gonna bother contacting the sellers since a) I barely know for sure which console came from which seller, b) it's all fairly easy to fix, and c) they've all come across so illiterate and hostile in their communication I halfway expect them to reply with threats if I'd merely suggest they sold me less than was advertised. Powering through.

When writing my previous post I didn't have time to address the other 2 things I've been looking in to: 1) securing the GPU heatsink, and 2) sales. Let's start with the simple one. For now I've found 3 ways to attach the GPU heatsink. The first is by retaining the original plastic bracket, cutting away the part that's now blocked by the interposer. It works, but there's some tension between the interposer and bracket, slightly deforming it. It's also pulled down in only 2 spots, which isn't ideal either. But the clamp is still effective, so it's a viable option. Second way is the same as one of the CPU options: using thermal adhesive. Simple, effective, sufficient but also unserviceable. Probably better than using the bracket though. No picture because there's nothing to see The last method I'm evaluating is by using a clamping bracket that slides over the heatsink, and will reuse the screw holes present in the case for securing the motherboard itself. By far the cheapest method of having something produced in a cheap and timely manner is by cutting a PCB to that shape, so I've ordered a bunch at 2.4mm thick FR4. I hope it's sturdy enough to properly clamp it. At least the printed-to-scale paper cutout fits fine. The other topic I want to address is about "sales". Although I've been doing console mods for a decade, it feels I've never been particularly good at commercializing my efforts. It's never been a priority to me, my focus was usually geared toward being able to move on to the next interesting project. And that has been sufficient before: I'd take on a project such as creating or building an open-source (hardware) project. PCBs and parts are always much more efficient to purchase as a larger batch than singles, so I'd generally buy enough for 5 or 10 runs, mod my own console, and offer 4-9 of them for just-above cost but enough to recuperate the cost of my own mod. A self-sustaining kind of hobby, that idea. Initially I wanted to follow a similar approach with this project, but I'm reconsidering that, for reasons I'll divulge. First off, I really underestimated the amount of time one of these conversions takes. It's a long list of activities starting with acquisition of parts, cleaning the console, rinsing + ultrasonic, drying, softmodding, converting to TSOP, RAM upgrade, recapping undoing clock cap damage, cleaning optical drive belt, tuning laser if it reads poorly, removing the CPU, cleaning the board, reballing the interposer, soldering the interposer, BGA xray inspection, soldering the interposer components, soldering the (optional) clock reduction circuitry on the interposer, undervolting the CPU, cutting the heatsink, and finally stress testing for >24h. When all goes well, without distractions or setbacks, it takes 4.5.5 hours from start to finish. I'm okay with doing that once or twice without the expectation of financial compensation, but I now realize that after the 3rd, it turns from hobby into serious labor. That realization also prompted me to rethink what kind of monetary incentive I'd like to pursue when continuing this work. One factor to take into account is the amount of investments I've already made or committed to thus far. After tallying up, the counter sits at over €4k. Truthfully, that has been an eye opener today, since I hadn't properly kept track of it. It should be noted that this number includes the parts for roughly 20 builds, but also the xray device (~€1000) + CPU test setup (~€150). That to me another indicator showing the project has progressed from hobby territory to something more serious. Furthermore, I looked at the equipment used during those 4-5 hours per conversion, and found that no hobbyist can reasonably be expected to carry even a subset of the tools employed. There have been some workshop pictures early on in this thread for those interested. After some reflecting on the many, many months of wages I've pumped into building the lab over the years, I lost the sense of obligation to offer services necessitating the use of such machinery at the aforementioned "hobbyist rates". Next, no matter the quality of work, we are dealing with (soon) 20+ year old parts operating well outside their originally intended specifications/environment. There's a real part of risk there, even if everything initially passes stress tests. If I want to professionalize this service, this is something to think about ahead of any unforeseen drawbacks. Thus far I haven't written anything tangible yet in terms of where I'm going with this, so let's get to that. In short: I want to find a good balance where I can professionally and sustainably offer this CPU upgrade as a service, without losing interest due to lack of compensation, without getting swamped in work (there's been SO much interest!), while covering potential risks. At the same time, I very much do enjoy working on videogame consoles. It very much is a hobby, and I do not ever want people to feel "ripped off" when there is no other choice to buy from (hint hint aliexpress Nintendo switch modchip sellers profiting off my firmware). Since this is a service, I want to offer some flexibility too. Therefore, I am going to offer these on a website with a small configurator. Some parts will be made removable (i.e. RAM upgrade), some parts will be made optional (i.e. open-xenium addition). Finally, I want to charge a price that is satisfactory to me, while people do remain willing to pay for it without the sense of being taken advantage of. I hope to have found that price level after careful consideration: the base price will be €350 + shipping.

Another update about thermals and wrapping up the first few boxes.. I've been evaluating different solutions for temperature management. Attaching the heatsinks using thermal adhesive provides acceptable results. It's also very simple and cheap. But it is also quite permanent, barring extreme dedication to remove it without causing damage. Less obvious to realize is a screw-mount solution, but if feasible it should be able to maintain similar or better temperatures, with the additional benefit of serviceability. I've toyed around by modifying the chosen heatsink slightly and came up with what I think is a good solution. I want to evaluate adding tension to the top-left corner using a zip-tie so further reduce possible tilting and guarantee tighter contact overall. Time for some pictures. Lapping the CPU IHS, this seems to have slightly beneficial results: For the screw-mount solution of the CPU heatsink, I've dremeled away a bit of the edge fins so make room for a spring-tightening screw. Not the prettiest, but effective nonetheless: More later on my plans with the boxes. I want to approach the project more professionally than I have until now, and this has some implications, both on pricing, availability and quality.

Interesting upgrade. Are you looking into using different RAM types entirely, such as DDR-333/DDR-400? I'm gonna see if I can complete a first 1.6 with 128MB + 1.4GHz combo.

Bit of an update as I'm wrapping up the first units for sale. The lower heat sinks I got are rather wide and count 30 fins while we only have space for 9. So I got a suitable cutting disk for this miniature bench-top table saw that's been sitting idle in the garage for maybe 8 years. Gotta go slow, but the result is tight. The black anodized finish looks pretty slick I think. After attaching to the board: Lastly, I decided on using a small screw terminal for optionally wiring the switch for the clock reduction circuit. This should leave the option of installing the switch very accessible to anyone. I intend to offer the first 3 units for sale tomorrow, and more will follow in the coming weeks.

Slight update: I've been looking into cooling approaches. These CPUs run much hotter than the original despite the lower vcore, and the original heatsink mounting solution cannot be used since a) the heatsink is too high to fit under the HDD caddy, and b) the interposer protrudes over the mounting holes for the original bracket. For a first quick experiment I used an angle grinder to cut the fins of the original heat sink so it would fit under the caddy, and used "electrolube thermal bonding system" since I had that available to secure the heat sink onto the CPU. Results were catastrophic since the console would shut off after about 10 minutes due to overheating. Next I inquired with n64freak for advice and he actually suggested an improved version of basically the same idea. He uses a commonly available and slightly lower replacement, with better quality thermal glue. I've since obtained the same heat sink and purchased the (supposedly) best thermal adhesive I could find. Additionally I sanded the heat spreader on the CPU with up to 2000 grit, with the end result looking like very smooth copper. The flatter the better, as while thermal compounds do transfer heat, direct metal-on-metal contact is much better still. Result: temps between 60-65°C at 20% fan speed while running games for over an hour in 30°C ambient. This matches reports of temps on Trusty boards as well as n64's own experience, so problem solved. Additionally I verified the working of the clock reduction circuit. After debugging the circuit from begin to end, I realized the STPCLK signal was fed a 32.768MHz signal, whereas that should've been a 32.768KHz one... This causes the CPU to nearly halt since it can't stop/resume the CPU clocks that quickly. Easy to fix, hardest is sourcing a suitable replacement. The original solder pads are spaced ridiculously far apart because the part was larger than anything currently for sale. Hopefully the part I found fits properly, and if so I will initiate stress tests before offering the first couple of boards for sale.

Considering that the cost of shipping a board over to me would likely exceed the price of finding a decent used console locally, I will primarily be offering boards that I sourced myself. For pricing, I'm thinking to sell them for €235 + shipping at cost. So that's for an upgraded xbox motherboard with Tualatin CPU at 1.4 GHz/512/133, RAM upgraded to 128MB, fresh capacitors and cleaned console shell. For transparency: parts total about €135 and I'd like to make €100 off of the labor involved. Because of the weight of the HDD/DVD drive, it might be preferable not to include them since their added shipping cost exceeds their value, so those are optional.

Been a while since the last update, but I'm happy to report that my process has become reliable at last. Last few builds have worked right out of the box, so I'm gonna look into offloading a first few soon. Not quite sure of pricing yet and what kind of 'packages' to go with. I'm leaning towards the following: - RAM upgrade to 128MB is always included, no opt-out - Caps always replaced, no opt-out - Optional openxenium, else TSOP - Case+DVD+HDD can be included for the price of shipping. Input/suggestions are welcomed too!

Didn't have too much time last night, but experimented with the idea of manually tenting via's within the BGA area. I applied a thin layer of UV curable solder mask over exposed copper that wasn't part of any BGA pads, cured it, and then mounted an interposer. This appears to have prevented any bridges from forming between solder ball and nearby via. Ideally this wouldn't be necessary and I do intend to figure out how this happened in the first place, and how to prevent it from happening, but this appears to be a simple workaround. I'll complete the install on this one tonight and hopefully book some success with it. It's about time.

No, CPU removed. I do intend to image them directly after soldering the interposer.

I've put the conversions on hold for a little while since my installs after the first successful one didn't work no matter what I tried. Cleaned up my soldering profiles, ensured my alignment was dead on, sought help from very knowledgeable people including N64 himself, to no avail. At some point I stopped counting, but I believe I registered 9 or 10 failures and decided to take a step back, since the time wasted for no results became a source of frustration. Uploaded some pictures here: https://imgur.com/a/z0YPuoN Ultimately I decided the sensible continuation would be to employ an x-ray device to verify correct soldering of the interposer. I found a dental device that I could accommodate with my budget and the device has since arrived. The sensor area is small (21x21mm) but resulting images are surprisingly usable. Can't tell for sure if this will allow detection of voids or head-in-pillow easily, but certainly I can identify spots where the balls floated slightly. I will adjust the interposer reflow profile to remain above liquidus slightly longer. More updates soon!

As I laid down in bed I couldn't contain my curiosity since I was still so perplexed that the 3 attempts after my initial successful one failed. I needed to check. The first board I used was a 1.4, the others were 1.0. Could there be a big difference in alignment between them? The top of the board sits very close to an SMD cap. You judge! On a 1.4, it's close but it fits: On a 1.0, oops, that'll elevate the interposer and certainly not benefit the soldering quality: I'm fairly assured this caused the poor BGA alignment. And so we learn. More later this week.

Time for a minor update. Not a very happy one just yet but new ideas for improvement did spring to mind, so I'll use this post to share some ideas I had. First, I believe @Bowlsnapperhad some concerns about aligning the interposer to the board "blindly". There's no need to go in blind, in fact, we can make it foolproof. I measured the silk screen print accuracy on the adapter and on the motherboard with a digital caliper. There's only about 0.1mm difference in outline width/height between the interposer and console boards. They're also accurately spaced around the solder pads, meaning this outline actually makes for a pretty decent calibration opportunity. What you can do it apply some kapton tape along the silkscreen outline on both the board and the interposer. Then, just make sure the tape aligns, and you're guaranteed a very reasonable alignment. And then you just overlay the crosses: When soldered down, it's probably still quite possible to remove the tape by pulling it down and wiggling it out. Or you can just cut it near the sides, no big deal either way. I'll use this method to verify my split vision system's accuracy on my next attempt. Since I'm not picking up the interposer in dead center, I'm no longer convinced the placement is as accurate as the visual indicates. This will either confirm my suspicions or rest my mind.

I'd recommend the ACHI for sure. Aligning the interposer isn't too hard. The top end of the board nearly touches a capacitor on the top. For the horizontal alignment, just turn the interposer over, align the balls by eye and rotate the board around while keeping the same lateral position, then shove it up to that capacitor. The good thing about BGAs is that you're still fine even if you're just under half a pitch off. That's 0.6mm of margin! While everything up until now has been smooth sailing, I've ran into the first snags today. An eBay package with Tualatins arrived, and even though I ordered only 2 from the seller, I actually received 3. Sadly, one doesn't work. Not a loss overall, but still, this kinda indicates there's bad CPUs out there. I'm now glad that I purchased a socket 370 motherboard solely for testing. The other problem I ran into today manifested on two boards: the interposer tilted when soldering it down. I didn't initially realize this on the first board and have already soldered on the CPU there, but obviously the system FRAGs. Inspecting very closely under the microscope reveals that only the very corner ball is floating over the motherboard. The balls just 1 pad closer to the center have soldered but they are obviously not ideally squashed. Reason for this must be that the weight of the interposer board rests only on the BGA balls, but the board protrudes over the BGA area. I'll have to remove the CPU and reball this one unfortunately. I set this board aside before making this realization, and soldered a 2nd interposer on another motherboard. Close inspection of that one showed the clearance between interposer and xbox wasn't perfectly even, and pressing in the corners flexes the board slightly. Will have to reball this one as well, but this gave me an idea for a fix. The 0.76mm balls when soldered down are roughly as thick as 0603 passives. The board is already resting on a set of 4x 10k 0603s on one side, so we can use such 0603's to support the board in the far corners. I soldered 2 resistors with one end to via's near the corners so they won't slip away, but they serve no electrical function of course. I then continued to attach another interposer to this 3rd board and it came out perfectly. There's zero flex, the balls are squashed very nicely, and the clearance is perfectly even around all edges. I'm confident that the issue's found and remedied, and I'll verify that tomorrow if my wife lets me on Mother's Day