I had a hook do same thing. It ended up being a burnt rom leg on the mpu board for the video. It was several years ago and I dont remember the location on mpu, but it was just a burnt leg on the rom. The information from the mpu was not getting to the dmd. The hook would show boot info only and nothing else. There is a chip on mpu for video and that was my problem. Good luck. Not sure this helps, but your issue sounds like the same problem I had.

Necromancing this thread - did you ever solve this issue and what did you end up doing? Thanks!

Bump... would like to know the outcome. Thanks

FWIW, the DE 128x16 DMDs have their own integrated display processor and associated display ROM. When the DMD boots, the display processor shows the display ROM version and then waits for commands from the CPU board over the 26-pin ribbon cable.

If you're just getting the boot screen and nothing after that, there's a communication problem between the CPU and display processor through the 26-pin ribbon cable.