• A review of JLCPCB

    05/02/2019 at 13:45 0 comments

    Full disclosure: I was contacted by a JLCPCB rep offering to do a few boards for me in exchange for a review.  I should further note though that I have done business with them as a normal paying customer in the past.

    I used JLCPCB for my current board version for my Water Alert project. I also did a slightly updated board version of my Attiny Micro board, had them do a few additional boards for my Atmega328P Target, and for kicks some Sega Gensis/Megadrive cartridge PCBs from a design I found here.  

    The ordering process was easy.  I really like that they show you images of the uploaded gerber files and in this instance it pointed out an issue.  For my Atmega328P Target board, I noticed that a portion of the silkscreen was distorted.  Under KiCad everything looked fine. I looked up their instructions for exporting gerbers in KiCad and saw that the include extended attributes option was checked in their screenshots.  I went back in KiCad and did that and resubmitted them.  The silkscreen issue went away.   

    The PCBs arrived quickly via DHL for a total turnaround time of about a week (I normally use the least expensive shipping option that usually takes a few weeks, but since it was on them chose the fast option.) They arrived in vacuum sealed packaging (usually they arrive neatly stacked in the package, but it's not really a big deal.)

    Overall the PCBs came out quite good.  Alignment was good.  The edges of the boards were nicely routed. Silkscreen text is nice and sharp (with the exception of R4 and R5 labels on my Water Alert board, although to be fair the text is a bit small.)  Order numbers were printed on the boards.  One thing that I'm really impressed is that JLCPCB is able to get soldermask between the pads of fine-pitch surface mount component footprints as shown on the Sega Genesis/Megadrive cartridge PCB (note that although I didn't specify gold fingers on the edge connector, it should be specified if you're doing something more than testing/prototyping/just tinkering.)

    My recommendations to JLCPCB:

    Give us the option to change the PCB quantity before the order is submitted.  JLCPCB changed their default quantity from 10 to 5 and I didn't notice until I uploaded everything.  Since one the boards had to be manually approved it would have been a bit of a wait if I just deleted the order and started over again.

    Retain promotion offers when an order is cancelled. On a previous order, a free shipping promotion was offered.  There was an issue with a board I uploaded so the order was cancelled. When I re-uploaded with the issue corrected the free shipping promotion didn't re-appear.

    In summary, I'll give them a thumbs up. I'd also like to thank them for offering to spin a few PCB designs at no cost in exchange for a review.  I currently don't have a regular stream of income at this time so saving anywhere I can helps greatly!

    https://jlcpcb.com/

  • Restoring a SNES

    04/10/2019 at 15:30 0 comments

    Over a decade a go I got a SNES from some relatives.  When I was doing some cleaning I decided to pull it out.  After cleaning the cartridge slot, it was working but the picture on the TV was pretty terrible. I picked up a cheap composite A/V cable and the picture was fine. I initially thought that the RF switch was crap, but upon further inspection that wasn't the case.  This is where the restoration began.

    The SNES RF switch coax jumper uses a stranded core vs the normal solid core that's used on most normal 75 ohm TV coax.  This means that the stranded core can't be used as the center pin on the F connector, so what  Nintendo did was attach a solid piece of metal to the end of the stranded core to serve as the center pin. The metal bit tends to be held in place loosely.  Why they didn't simply use standard solid core TV coax is anyone's guess.

    The problem was surprising and yet unsurprising

    The less than spectacular coax jumper made me think that it was the root of the problem, so I planned to replace the coax jumper.  When I opened the little grey box, the actual problem revealed itself. Two of the three solder joints that connected the coax to the PCB were completely broken; the coax shield joint and a joint that held a piece of metal that was crimped to the coax outer jacket to help hold it down to the PCB and therein lied the flaw that caused the failure.  The crimped metal piece was the only thing that provided any strain relief.  the RF switch is often dangling off the coax connection on the back of the TV so quite a bit of stress gets placed on the connection of the coax to the PCB.  Sadly I didn't think to take a before photo, but I marked the joints that were bad in the after photo below. I also used some hot glue to help provide some actual strain relief so that it doesn't happen again.

    After that, I re-assembled the case and plugged it into the TV. It worked just fine. Surprisingly the iffy center pin didn't cause any issues for me.

    The next chapter in the restoration was cleaning up and retrobrighting one of the controllers.  The controller wasn't exactly treated nicely by its previous owners and needed a bit of work.  I first disassembled the controller and gave it a good scrubbing. I took a magic eraser to the badly scratched up areas which helped a lot. 

    Next was to hunt for something around the house that could serve as the retrobright solution.  After a bit of googling, I learned that many oxyclean stain removers can be used for retrobrighting and the key ingredient to took for was sodium percarbonate which is apparently a source of hydrogen peroxide. I found a box of Biz laundry stain remover in the laundry room as a possible candidate. I looked up the SDS to find out the ingredients and while it didn't list sodium percarbonate, the SDS did list disodium carbonate and in the parenthesis it mentioned compound with hydrogen peroxide.

    I added some Biz to a container of water and stuck the plastic controller pieces in it and set it out in the sun for 6 or so hours.  While the result was less than perfect there did appear to be an improvement but the controller wasn't terrible yellowed to begin with. Below and after photos below.

    Next came the real challenge, the SNES itself. It was badly yellowed with the exception of a few case pieces that remained the original color.  I made a crude, but effective makeshift screwdriver bit from an old flat head screwdriver to remove the security bits to take the case apart.  After taking the case apart, I gave everything a through scrub. I then filled two tubs of water and mixed in some Biz.  I put the two large case pieces in each of the tubs plus a smaller piece and put them out in the sun for a total exposure of around 14 hours. It made quite a transformation. While it didn't work perfectly, it made a major improvement. 

    ... Read more »

  • My thoughts about the 2019 HaD prize

    04/08/2019 at 20:32 5 comments

    I was at first happy that the annual HaD Prize started up again. This year I put in two entries.  If anything else, I would get a few $ of seed money to go towards buying supplies to work on my latest projects, or so I thought.  Upon reading the rules for this year’s HaD Prize (and also getting it confirmed by a staff member) I learned that only projects that make into the top 20 in the first round will receive any seed money, a bit of a letdown to say the least.

    One of the most appealing (if not the most appealing) things about the HaD Prize vs many other contests was that even if you didn’t win any prizes, you could often get some seed money at the very least.  It’s why I’ve bothered to put in entries for the HaD Prize.  I know I wasn’t likely to win anything big but I’d at least get some money to fund my projects.  If this ends up being the norm for future iterations of the HaD prize, then there’s practically little incentive for me and many others to enter.

    This year's focus to design a product for mass production does seem out of place.  Most projects here aren't things that the general public care going to want to buy off of store shelves, so it's doesn't make sense to design to spit out thousands.  For my hardware designs I’m more focused on the design to be easy to assemble by hand and keeping costs down.