MIDIbox SID-NUXX PCB Error
The reason for the short…
I thought this project would be completed tonight. I guess not.
That right there is what I found after removing the power connector from my final MIDIbox SID-NUXX PCB. That small bridge between the annular ring and the groundplane just happens to be on one of the AC power lines, and that has cooked two of my wall wart type power supplies. This isn’t a huge deal, but I was looking forward to having everything done tonight. Now, beyond trying to fix or replace the two bad PSs I need to unbox and check over the boards in both of the kits I’d assembled. < sigh >
For reference, that photo is the same area as the three large holes in the outline labeled PWR in this photo.
I guess they’ll go out in a few days. I don’t want to risk this with them, though. Mine will be easy (enough) to fix with a Dremel, as will the others if there are problems. I doubt there will be any found, but I’d rather that I find them now than have other people be stuck with potential weirdness.
Also, I’ve learned to put self-resetting fuses in all my power supply designs from now until forever. Not that this would have helped here (if I’m thinking right the short really took place between ground on the bridge rectifier and half the AC signal), but it still should be done.
Ah well.
At least Danielle and I swung by the cider mill today and grabbed six gallons of Yates finest. Five of these are sitting in a sanitized carboy in the basement having recently received a room-temp yeast inoculation. With any luck there will be wee bits of foam on the surface in the morning, and tomorrow I’ll have a fully active fermentation. Now to decide what to do with the cider. Thus far it only has yeast, yeast nutrients, and two pounds of honey in it. I’m thinking maybe a few (five?) pounds of berries would do well. Blackberries would be nice, but maybe strawberries…
Now, bed.
While many places will quite a 0.005″ tolerance, this isn’t always the case, especially near hole locations. I’ve usually had good luck running traces between DIP-socket holes, but even then you need very narrow traces. It’s kind of a geometry similarity thing, how the flaws can form. Two concentric circles are more likely to run together than a thin trace running beween two holes.
)) vs. 0|0
Sucks, though, that they made that flaw. You may be able to send them back and have a new run made. Have you tried contacting the board house?
Granted that is a definite flaw in the manufacturing process, and not the design, but you probably shouldn’t have your ground plane surround your vias and plated through-holes quite so closely. Leaving a larger gap will reduce the chance for such problems in the future. How large was that gap supposed to be?
Those should be 20mil, which is plenty of space. Since I’ve only seen a defect on one out of the three boards I’ve checked thus far, I think things will be fine. I’ll go over the others and be certain. I’ll probably send the photo off to the board house and ask them for at least a replacement for that one. May as well, eh?