Thanks for the assistance. I like the added capacitor idea and removing that jumper. I didn't realize a cap was needed? But that jumper was sure throwing me a curve. One of the reasons I thought my tracing of the example was not correct.
Probably should have asked this before, but I have a couple more questions about the circuit. 1. - What would one be programming with that jumper? 2. - Does the 3k resistor have something to do with the programming, and is it (or any other value resistor) really needed in the output section? I didn't understand the purpose of the resistor either?
I started out with the LTV-8141. I wasn't aware of the PS2505s? They look to be similar and have the same pinouts. I had also given some thought to the 8441 (or now 4 PS2505-1s or PS2505-4) so I'll change that and try to use the 16-DIP size. I suppose one could then use the same PCB for a 1, 2, 3, or 4 input/output version.
Earlier I was thinking about 1, 2 and 4 in/out versions on separate PCBs. Reason being, I did some fiddling with a through-hole PCB for the 4 in/out version and thought it may have been a bit large for OSHPark. Prices go up quick after a certain size of somewhere around 1 square inch, maybe a bit more. My thinking was the 1 or 2 I/O versions might be small enough for more economical pricing from OSHP. But, I haven't actually priced anything, just guessing so far.
For the final PCB(s) my thoughts were to make a post about it and add it to the 'Projects' list. It would be just another option for anyone that has an interest. Hopefully there would be some interest? Now I'm thinking I should probably get a sample of the boards made first, just to be sure they work properly before someone else (if anyone) tries them out. Wouldn't want them to get something that didn't work.
I also like the idea for the power shut down function. This might also be appealing to some folks here. Might be in for trying that one myself. Regardless of project interest, I do enjoy all this, always learn something along the way, get a new circuit design and have something new to fiddle with after samples are assembled. As an added bonus, if they don't work the first time, I get to try it a second time.
