Sure. If Evan can wait till next week and Eagle or Altium is fine. Sent from my Verizon LG Smartphone ------ Original message------From: systems_glitch via vcf-midatlanticDate: Wed, Aug 29, 2018 11:48 AMTo: vcf-midatlantic;Cc: systems_glitch;Subject:Re: [vcf-midatlantic] Schematic work needed Sounds like we've got plenty of volunteers, then! :P Thanks, Jonathan On Wed, Aug 29, 2018 at 11:45 AM alan--- via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:
It's two 8 bit opposing latches and some address decoding glue. If one knew the port address, you could create the schematic blind and be 98% correct. Sent from my Verizon LG Smartphone ------ Original message------From: Kyle Owen via vcf-midatlanticDate: Wed, Aug 29, 2018 11:17 AMTo: vcf-midatlantic;Cc: Kyle Owen;Subject:Re: [vcf-midatlantic] Schematic work needed On Wed, Aug 29, 2018 at 10:05 AM RETRO Innovations via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:
Many of the signals go under the ICs. Sometimes, you can hold to a light and see through the PCB and validate where they go, but other times, I have missed wires connecting to more than 1 pin of the IC under the IC. Ohming, if applied verbosely for each signal around the IC compared to each IC pin, should find all of them, but I don't think I would promise 100% perfection without spinning a PCB and testing the completed unit.
Maybe everyone else is better at ohming out boards and the hidden signals under ICs never bother anyone else, but I've gotten hit twice by them on two different efforts.
Yes. If you do not completely ohm out each pin/component, I could very much imagine generating an incomplete schematic. The netlist generated by ohming out the board should have every pin on every component by the time you're done. If not, you've missed something. With some conditional formatting, it's possible to highlight possible errors like duplicate entries, too many pins per component, etc.
Hidden traces are no problem *if* you are not relying on visuals, but rather the ohmmeter.
And if you're using a Fluke, don't forget to hold down the yellow button when turning it on, lest you have it automatically power off while you attempt to ohm out the board. Ask me how I know... :)
Kyle