Yes, it does involve a lot of observing. I am using machine sockets and I check my soldering with a magnafying glass for a visual check, then I check with my meter for shorts between pins. So I must be missing something. One of my other goals with this project is to add some logic circuitry that I already have working on another VIC 20, that will give me banks of RAM underneath the kernal, basic and character ROMs, just like the C64 does. I hope to port that logic to CPLD.

Murphy's Law -- and nobody is immune!

Other stuff to look for:
- schematic error (eg: pin number mis-identified)
- wiring error (wiring doesn't match schematic)
- '573 lacks proper GND and +5 connections
- defective '573? Unlikely, but a shorted input pin would upset the VIC

Happy hunting! Sounds like you're getting close.

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In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html

I would post pix, but they all seem to be too large for this forum, even zipped.

Use any image-editing software to scale them. Nobody wants to have to scroll to see the whole picture. I use GIMP which is much like Photoshop, in fact had healing features before Photoshop did, like to remove littler from the grass in a park, remove a road from a desert scene, remove a wreath from a paneled wall, etc., and it's free. Go to Image-->Scale Image... I always scale every image I post down to a decent size, like 800x600, 640x480, or whatever is the smallest that shows the necessary detail. I usually also crop, sharpen, and improve the contrast and brightness and so on too, but to just scale the image is really quick. See http://www.gimp.us.com/

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

I finally got some photoes of this VIC 20 sized down. The wires are all part of making the VIC 20 work directly off the OUT1 and OUT2 from the 6560 and only feeding the 6502 from OUT2, making it easier to put the 65C816 in. I can pull the 65C816 out and put the 6502 back in and it will still work.

I have finally found some time to work on this some more. My problem with splitting off the bank address lines from the data lines is solved. CPLD's are so nice to work with. The original, non-working, logic used a tri-state buffer with an active low enable, just like an LS245. I'm sure I read somewhere, to use an active high enable, so I tried that, and it works. I will have to look at the 65C816 data book to see why, but now I can get on with the rest of the logic. Thanks to everyone for your help and suggestions.