PCB looks beautiful!
I'm still interested in one of the 5 extras if/when they become available. I recently came into posession of some lovely Vintage German ISO OG Doubleshots and don't have a PCB for them yet.
Off that is so nice!
If I can't make the other 5 PCBs work, Jae will stock Doddle60 at his store, so you are pretty much covered!
what could go wrong? legitimately i wonder because manufacturing technologies has gone very far and now most IC are pretty much insensible to heat and static and i guess the pcb being checked at the factory should not have defects?
i am also asking because i am planing on making a few projects that require custom pcb (not keyboards though)
i was thinking for the 5 extra, i did not see why there would be a failure at this point, i see why prototyping is a good idea and having assembled a few pcb i did maybe ever killed one with my old non regulated soldering iron, so i guess that someone less amateurish than me should have even less trouble getting all working if the design is proven working?
Ok, so big wall of text incoming and I don't want to lecture anyone, I'm just explaining my thought process here and why I have so strict QC.
Fist of all, a design flaw is always possible. No serious engineer on Earth will expect a prototype to work first-time. The Doddle60 had two versions prior to this prototype -- I wouldn't be crazy to get money feom complete stragers in other half of the globe and send them a PCB if I didn't know this was working.
Supposing that the design is fine (which it is, I have assembled 6 PCBs so far and all work wonderfully), the production line is still filled with possibilities for failures. Bad plating, bad cuts, bad finishing, bad soldermask, scratched PCB, bad logos. All of these have happened to me using reputable and big PCB manufacturers.
In the fabrication side, I have come about inumerous PCBs that had a perfectly fine project but there were faulty traces or components that hindered functioning. It is not uncommon, specially with prototyping units. I did use PCBWay, which is a fab known for less failures than the competitors, but it can still happen. Had I used JLC, for instance, which is known for cheap PCBs for prototyping, the failure rate can double.
In the assembly side, we can talk for hours on what could go on. I can heat up the MCU too much (which is still pretty sensible to heat, no so much to static), I can lift up a critical pad on the connector, I can scratch a trace, I can scratch the soldermask off, I can make dents or scratches that make a PCB aesthetically not pleasing, I can make a wrong solder connection, short two signals and fry a component off. I consider myself a professional engineer yes, but I am not foolproof, I have to avoid the arrogance of the title, get some humility and accept I can screw things up. C'est la vie.
In a production line they use much more controlled and reproducible methods such as a reflow oven, which has a heat curve they apply to components and can make everything much more failure-proof, specially through automatization, but there still are chances. I invite you to talk to some vendor friends and ask them the percentage of PCBs that come with fabrication issues.
The factory does not check every single connection. Yes they have a flying probe, but get this. This PCB has 300 pads, making for a maximum of 300*(300-1)/2 = 44850 possible current paths which is simply unfeasible to test individually, so they test key traces and connections in hopes that, if those are fine, chances are all are fine. Mind you that given a number of n pads, the possible current paths are n*(n-1)/2, that is, grows quadractically such that the bigger the pad numbers, the higher the fabrication issues possibilities are.
Sometimes the PCB can simply come scratched, dented or C-stock that I'd not be comfortable selling anyone at full 35USD+ price. I have a name to hold and this is literally my first GB, I want to be transparent and QC strict as I can. My effort here is so that people can ask anyone in any Discord server about experiences with me and someone will say "yeah, I own a Doddle60 and gondo did a good job" instead of "I have a Doddle60 that came scratched and paid full price for it". That's what I gain here, reputation capital.
Through my 10+ years of messing around with electronics I can assure you that ~5% of the PCBs I assemble and test fail at QC, be it aesthetically, be it functionally, be it faulty components that I have to reflow or replace, be it because I screwed up. If I make a GB for 10 PCBs, I'm ordering 15. I didn't do that because I expect to sell all 15 -- on the contrary, it's because I can't expect the first 10 to all work.
