[vcf-midatlantic] Schematic work needed

Bill Degnan billdegnan at gmail.com
Wed Aug 29 11:07:22 EDT 2018

this is for a presentation slide, not to build the thing

On Wed, Aug 29, 2018 at 11:05 AM RETRO Innovations via vcf-midatlantic <
vcf-midatlantic at lists.vcfed.org> wrote:

> On 8/29/2018 9:49 AM, Kyle Owen via vcf-midatlantic wrote:
> > Why would ohming out this board not yield a 100% correct schematic? I see
> > no tricky components that would confuse an ohmmeter except the address
> > switch, which could be unsoldered.
> 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.
> Jim

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