Thanks for all the interest. I'm a little surprised at the amount of interest (considering most of these boards are available from other manufacturers and merchants). As a reminder ... I'm doing this for me (I like to learn new things) for the purposes of having a bench test rig that's more compact and supports multiple systems.
<TL:DR> - just scroll to the pictures if you want a summary.
If / when I get to the point of releasing these ... words of warning.
1) The boards will likely not be cheaper than the other commercially available products. These boards use the original components and there are more of them than re-engineered boards as well as using more robust parts (such as Littelfuse fuse holders rather than fuse clips). Using original components provides the greatest level of compatibility.
2) If I do decide to go with an option for kits (with components) it will not supply any of the more difficult or rare components that are hard to find. I source these from merchants in China (often via eBay) and there's risk that the components are either counterfeit or knock-offs. I can't accept the risk of warranting these components. Perhaps I might decide to provide them without warranty to people that are having trouble finding them.
3) Following on from that it's unlikely I'll provide kits because I don't want to warrant any of the components I provide (plus the hassle of sorting and bagging separate single components). Merchants you buy parts from can provide that warranty. I may decide to provide an option WITHOUT any warranty on the components. Sorry. I'm not a professional business - just a guy who enjoys the hobby where perhaps other people can benefit from what I've done by sharing these boards.
4) I might consider providing fully populated boards (for those that aren't adventurous with building their own) but again ... these won't be cheap. It's a lot of (manual) labor to build these. PCB manufacturing companies can wave solder which is much faster. I don't have those facilities. If anyone really wants one of these I could be persuaded to build one (when finally ready). These would come with complete components (as well as rare components) - a fully plug-and-play solution.
With that aside ... I've been working on testing the boards and getting them working focusing on the displays for the moment. I have success for all the System 11, Data East and WPC alphanumeric displays. The majority of the master display logic works but there are some minor errors that will need correcting and the WPC board is more screwed up than I thought (nothing I couldn't fix by re-wiring with prototype boards).
I know I have a friend who likes the traditional orange (or amber) but I'm kind of liking the white. I acquired a few different (common) colors to see how things turn out in actual machines. If people are interested in the displays I will provide the LED components as they aren't easily available (I had to make a reasonably sized minimum order quantity to get the components).
The following works (pictures below) - tested on the bench. Also tested was the RJ-45 data and power connectors and they work. The setup shown below is where the master display board is directly attached to the slave display panel (as would be used in an actual machine).
Williams System 11 (discrete 7x2/7x2/2x2) - High Speed to Pinbot. I'm going to try the setup in my Laser War at some stage but I expect it will work. I have every reason to believe it will. Note the status on the smaller lower panels. I checked it works with the discrete displays.
Williams System 11 (panel 7x2/7x2) - F-14 Tomcat to Swords of Fury. Unfortunately the double panel is NOT correctly placed for the 7x2/7x2 arrangement in an actual machine. I will need to make a (new) specific double panel for use in an actual machine. I need one for me as I have a Big Guns that doesn't have a display.
Williams WPC-89 - Fun House and The Machine.
I currently have no plans to make side-by-side panels that are used in Bally branded machines (such as Elvira). I don't have any of these machines.
I have plenty of other things to work through so it will be a while before any of these will be ready.