Just got a delivery from JLCPCB of my first prototype run of "the product". Aaaand I've found a mistake already, bloody Kicad footprint fuckery. Grr.
What's the source of the problem? How could it have been seen before manufacture?
I always use several different gerber viewers on my boards before sending them off. Tends to trap out my infelicities.
Pin assignment error in kicad library on a BJT. Before manufacture I actually reviewed all the footprints but I appeared to have missed the one that was wrong. It has been added to the checklist and will be reported back to Kicad team. Board run was only £11 and I can proceed with populating it and looking for other errors. I expect 3-4 board runs before I'm happy with it so I will see what else I can fix first. There are 105 parts on this board so I'm sure I've got some more trouble to go. That's what Kynar was invented for
Bummer. The respin latency may be more annoying than anything else, but as you say you can often do a lot of debugging[1] before that is necessary.
I trust the wirewrap wire is the traditional blue colour
Nitpicking: it wasn't KiCAD but the library.
[1] most entertaining case I saw was that a preprod ic set's data sheet showed the fabricators's pinout, i.e. from the pin side. First board got rather hot, followed by head scratching - and finally the realisation that the ics could simply be mounted on the other side of the board. Try that with SMC components!
It's not too bad. 12 days per turnaround for 10 boards at £11 which is pretty quick and cheap. I've seen the same service with 5 day turnaround here in the UK for over £500 for that.
The Kynar is not blue in my case. I did have a roll of blue stuff but used it all up. When it came to buy another roll I decided to get yellow as the contrast is better against average stuff on PCBs (RS 209-4798
)
Not sure that Kicad wasn't partially responsible here. The parts are inherited / derived from template parts so the derivation isn't as obvious as it looks due to pin numbering, which also isn't consistent between manufacturers, particularly the Chinese second source outfits. Typical example of the base BJT symbols, and then there's about 8-9 TO92 footprints on top of that, some inverted, some triangle layout, some inline, some with basically useless alignment semantics.
Good point with SMD vs TH there. Although at least you don't have the problem of working out whether or not the pinout is viewed from below or above which is sometimes all over the shop on datasheets. Can't remember which one it was, but I think it was TI who listed on their datasheets a TO92 package with both "top view" and "bottom view" next to the same pinout image