Silent Radio LED Sign

I have obtained two Silent Radio LED signs on Ebay and I intend on rebuilding them. To get one of them apart I had to reach through a hole in the back and cut the wires to the power transformer. To remove the logic board I had to use pliers on the screw head and pliers on the mounting shaft. In one case the screw broke off rather than come out. Tin sheers or heavy duty wire cutters can be used to remove the connectors between the sign and the logic board.

Once the board is removed the reverse engineering can begin. The pin-out is quite simple;
1. 5 Volts
2. Ground
3. Seven common Anode lines (5 volts to light up)
4. Seven common Anode lines (5 volts to light up)
5. Seven common Anode lines (5 volts to light up)
6. Seven common Anode lines (5 volts to light up)
7. Seven common Anode lines (5 volts to light up)
8. Seven common Anode lines (5 volts to light up)
9. Seven common Anode lines (5 volts to light up)
10. Ground
11. Data
12. Clock
These same 12 lines are available at both ends of the sign.  I broke a couple of runs when removing the logic board.  Maybe un-soldering it would have been a better idea?

My objective is to make a very simple straingtforward interface to run the sign from a PC. Perhaps use the PC's serial port directly, a 8051, a Basic Stamp or some other simple common controller.

Here is some of my old work on LED array signs;
http://sites.google.com/site/bobdavis321/led-array-projects

I have several posts on LED sign modifications. 
Check this one out for more on the Silent Radio Modifications:
https://bobdavis321.blogspot.com/2013/05/silent-radio-led-sign-to-arduino.html

Here is part three on Silent Radio signs:
https://bobdavis321.blogspot.com/2011/05/silent-radio-led-sign-part-3.html

And here is part four:
https://bobdavis321.blogspot.com/2011/05/silent-radio-led-sign-part-3_16.html

Here is a simple column driver adapted from one of my old schematics. The problem with this setup is that you cannot turn off the columns while updating the shift registers.  Perhaps another IC would work better? 

This is the error message it displayed on arrival: