here's the 1st version done with eagle 8.2.2,it's not perfect but quick reference for setup LCD ports, can help
revised TL431 drawing ans proposed LM4040 precision reference, ISP 6 pins header (in fact I have DB9 but it's ugly but simple to implement and good fiability)
eliminated socket and added pads to connect with female bananas on enclosure
SVR05-4 description is not correct,i'll remake the library part or search for a good one
best regards,
pierre
I will have to take down my filming setup to get to my desktop and check this out. Alternatively someone could greatly help me out by posting an image. I'd like to integrate or work with you to add this into my current project.
I am partially disabled, and do all my filming editing and illustrations from an old Samsung Galaxy phone. I am limited to sitting or standing for 1-3 sporadic hours total throughout the day on my good days. This means I'm super slow to complete projects but I can devote a massive amount of time to research editing and creating illustrations.
I am using the Sketch mobile app (like Microsoft Paint with more layering options) to map out the traces and edit the schematic. I still have and can modify these files easily. I uploaded them to the YT video as streamlined as I could so anyone can visually check my work. I didn't initially plan to add them but it seems like a good resource for all. The only file I can't edit easily is the picture of the PCB with the parts designators. I can remake it if need be but I mistakenly deleted the file this came from while managing my limited storage space.
I plan to add test points by demonstrating where to bend pins to allow easy test point connections. I also plan to show how to add the ISP header connections. I also want to add pin 1 of the TVS IC to either the Frequency measurement or Voltmeter circuit. The last PCB modification I plan to use on the first stage of this build is to add a trimmer capacitor to replace one of the 22pF caps at the crystal.
The project will get integrated into an old upcycled enclosure from a HP printer power supply brick. These are easy to pry open with channel locks, and they fit the PCB perfectly while leaving plenty of room for a small transformer and battery.
If I can figure out the programming side of this device (total ISP noob), I want to add the zener threshold tester, but I plan to use a MC34063 if I go that route.
...And if everything goes really well I'd like to look into adding a INA106 differential amplifier with a laser trimmed gain of 10. I was planning to build the milliohm meter from the Scullcom Hobby Electronics YouTube channel, but I think the diff amp might be more useful when integrated into this project. I would probably need help understanding the programming aspects involved to make this happen, but I think this little mod could be interesting.
The last thing I've been looking into is why "discharged capacitors" are mentioned, but only 'before the device is powered on.' I assume this is due to the TVS IC's need for power. If that's the case, why not simply add a 2 pole normally closed relay to short all 3 test leads with a short on delay circuit powered from the collector of the PNP transistor? Seems like that would solve the problem of mega-burns, but I've not done my research in this area yet.
The images for Power and Ground test points 1-9 to show in my next YT upload are attached.
Let me know what you think or if you think I should go in a different direction.
Thanks, -Jake.