5500 board won't POST/chime w/o the Display hooked up?

[Trash80toHP_Mini]

I've got a test rig that'll boot Alchemy and Gazelle boards, but not my AIO 5500 sub-variant of Gazelle. Does it fail to POST due to lack of internal CRT hookup or might there be another issue with this particular board?

If display is indeed the problem, will it POST with the external display/projector cable in lieu of the A/B CRT hookup?

 

[joevt]

Is the 6500/TAM emulation of DingusPPC good enough to test this? It might be missing some stuff that makes the emulated machine identify itself as a 5500 AIO if such stuff exists.

Would need to compare dump-device-tree and DumpNameRegistry and System Profiler and UnivTables low memory globals.
https://68kmla.org/bb/threads/skipping-the-startup-memory-test.50699/post-570896
https://forums.macrumors.com/thread...l-work-in-a-beige-power-macintosh-g3.2303689/
https://68kmla.org/bb/threads/how-does-the-l2-cache-work-on-nubus-powerpc.47395/post-572444