One new board that we have been working on for a while now is the magnet board used in Guns N Roses and a couple of other games including the much newer Stern Indiana Jones. The Homepin board incorporates all of the latest Stern changes and also the addition of the cap across the clock line as dicovered by a pinball enthusiast. The biggest problem we had was 'how to test the asembled boards?'
In the end I made some coil formers and wound three very heavy coils similar to those used under the playfield of Guns N Roses. Some custom software written to a PIC and I had the basics for a test jig. The problem testing this board (without a machine to plug it into) is that the board requires not only one of three coil activate signals but also clear and clock signals at the exact times to operate correctly and there really is no way of fully testing this board without those.
The PIC solves this by providing the signals exactly when they are needed. It sounds quick and easy but to write - debug - test - debug again - test - debug even further took several hours to have a fully functional test jig. I usually chop the appropriate section of 'ready made' PCB from a finished project/job as that makes breadbording much easier (the blue PCB in the pics).
I bolted the coils to a couple of pieces of ply I had laying about and screwed the other bits to that.
Here is the messy result:
Here is a finished 'test board':
and the test jig in action here:
Now that we are able to correctly test these boards we can start construction of them but finished boards probably won't be available until the new year now.
