Today I received the I/O board for Dodo. I patiently waited all day to assemble and test it. After a long evening of ups and downs it is now basically working. Unlike the main board, this new one has some serious design problems and will definitely need to be redone.

There are two large problems:

1. The Up/Down/Left/Right buttons are spaced too close and the caps do not fit as a result.

2. Two cartridge traces are incorrect. I was able to use a razor blade to cut the two traces and run new wires, but it is just a patch.

I also ran into a couple minor problems:

1. The mounting holes on the display are just a hair too small for the 4-40 machine screws I have. I will need to order different mounting hardware.

2. My LEDs have weird nubs on the leads that are preventing me from inserting them into the holes.

I now have a big decision to make. I was planning on eventually making more substantial changes to both boards to move some components from one to the other. Do I do that now? Or do I fix the known problems on this board and have it redone before making the bigger change? Something to sleep on.

This shows how the two boards will stack. Part of the big change I want to make is to move the DB9 connector to the top to get it away from the buttons. I also want to be able to space the boards much closer together. I will abandon the IDC connectors and go with a single 20x2 header like on a Raspberry PI.

I am happy with the way the volume control worked out. The game cartridge also fits perfectly.