I am very pleased to see this new design, well done! As an engineer i like the improved lay out, improved reset section and the use of a more modern memory in stead of a 5101 so we can use an NVRAM device like Dallas, Ramtron or Simtek more easily. Also the resetboard components are integrated, very nice. I agree on remarks from others about the plating, it can cause problems over the years but other than that it suits to my taste. If not already mentioned or designed like that: did you think about a jumper or dipswitch to override the slam switch input for older sys80B's if desired?

Related to the subject (i don't want to hijack your topic)....i did write a few test Eprom's inspired by Leon, also for Gottlieb system 80. There is a small movie from it at youtube (from an earlier version, i added some more things later). It does a more thorough job testing the memories, it tests also the switchmatrix inputs and the socket for PROM2. No problem to share it with you.

There is no ISR in Leon's test Eprom. It only tests the first addresslocation of each RIOT. But it cannot distinguish the 3 RIOT's from eachother, in theory with a stuck chipselect circuitry, you can test 3 times the same RIOT. It also cannot detect a broken addressline trace. If a trace is broken you write and read data to a certain address but not the address you think you are writing to. This are amongst other things the weaknesses in Leon's test Eprom. When using Leon's test Eprom or mine, it is always a good thing to check the IRQ line with a logic probe or oscillscope. If it is stuck to GND, you have to examine the RIOT's. But in many cases, if the IRQ line is stuck, the memory test also fails from the RIOT causing the stuck IRQ line.....

Very nice! Looking forward to see your results!

Looks great. Respect for your achievements and putting so much effort in this!

A bit off-topic: my testrom was written from scratch and based on Leon's idea, not on Leon's code. I started coding it in 2011 after talking with Leon if he was okay with that before he passed away. It was Applejuice his publication about this system80B remake which decided me to join Pinside and sharing my testroms which I was already using for some years. My posts earlier in this thread were my very first posts on pinside.

You don't need the TC1 connector to run my testrom on this board (and also original system80B boards with a piggyback). I provide 2764 binaries which you can directly run from the PROM1 (2764 gamerom/Eprom) socket. For indication of the testresults you will need to connect an additional LED to addressline 6. I don't know if this LED is installed by default on Applejuice his system80B remakes.

This is how I use my testrom when repairing all system80 boards; i made a piggyback to be installed at U3 (80, 80A) or PROM1 (80B). From this piggyback I can run the testcode in a 2764 Eprom. It also has an LED installed indicating the testresults. It actually is the same thing Gottlieb made for their system80B boards only with an additional LED connected to a6.