I got my Replica 1 recently and finally sat down and put it together. It worked the first time (I was impressed since I am a true novice with a soldering iron). It has successfully reminded me why I loved the 3 semesters of assembly language I took in college (graduated in 2001). However, the one thing that is NOT working like it should is the Serial I/O board, so I was wondering if anyone has any advice. When the Serial I/O board is plugged in, the Replica I operates as it should, but I don't think any data is being sent out over the serial port. I've got it hooked up to my Powerbook through a Dynex USB to Serial adapter (uses Prolific chipset). I haven't had any problems with the adapter, but the Mac drivers are a little flaky (but EVERYTHING I've tried will work in Virtual PC when it uses the PC drivers). When I've got it connected to the Replica 1, it does not appear to send/receive any data at all (I tried with ZTerm on the Mac and HyperTerminal through VPC, both produce nothing). I've tweaked everything I can think of with the connection, but have had no luck.
What type of serial cable to you have standard or null modem. This determines where the transmit and receive signals are on the connector. I haven't played with zterm in a while, but when I did, the serial adapter I have for the Mac Classic II was null modem type so I also had to use another null modem cable to correct the wiring.
Things to try to see if you serial port setup is correct:
On your Mac with the serial converter, connect a wire from pin 2 into pin 3 (make sure you get the correct pin # or you could cause damage). With you make anything you type in zterm should get sent back and typed on the screen. If you get nothing, problem is in the serial adapter still.
If this works figure out a way to do the same at the end of the cable where it plugs into the replica. You will probably need a gender bender f/f DB9 to do this feature. Once you have that working try the replica again.
There is a way to do a loopback test on the replica which would create double characters but we'll get to that test later.
See how these tests work. I do remember having issues with zterm but once I got it working, all was good.